Btx cooling: BTX Cooling and Airflow Explained

30 ноября, 2022

Difference Between ATX and BTX

A motherboard, also known as the mainboard, is a large circuit board that sits inside the computer case and connects all the essential components such as CPU, RAM, expansion slots, and hard drives, etc. They come in different forms and sizes and are called form factors.

If you are aware of motherboards you may have also heard the terms ATX and BTX. They are a form factor of motherboards and play a very crucial role in improving the PC’s performance and versatility.

In this article, we will discuss the Advanced Technology eXtended (ATX) and Balanced Technology eXtended (BTX) to help you learn basic differences between them and see which form factor is better. So, without much further ado, let’s start.

Outline

What is ATX?

Advance Technology eXtended or ATX is the most common form factor of a motherboard in the computer world. But this was not the case until 1995. Before ATX became a standard form factor, motherboards used to come with Advanced Technology (AT) design.

However, AT motherboards lack capabilities and needed replacements. This is where Intel grabbed the opportunity and introduced ATX which became a successor of AT in terms of speed, interface, and performance.

The introduction of ATX is considered one of the biggest changes in power supply design, motherboard, and computer enclosure as it improved standardization and interchangeability of parts.

A full-size ATX board is 12 x 9.6 inch which is considered a standard form factor. A Micro-ATX or mATX is 9.6 x 9.6 inches making it a perfect option for budget-friendly gaming PCs, but the availability of PCle slots can be an issue. Then comes an EATX motherboard variant which supports dual-socket and larger surface area dissipate heat better.

Pros and Cons of ATX

Here below are some pros and cons of the ATX motherboard that you must know.

Pros:

1: Expansion – the sufficient size of the ATX form factor allow enough slots and ports for expansion.

2: Upgrades – because there are lots of ports and slots in this motherboard, there will be no hindrance when and if you upgrade your system.

3: Interchangeable parts – the ample size of the ATX motherboard allow you to remove or add parts to your motherboard.

Cons:

1: Blocks airflow – the arrangement and position of components placed in an ATX board can disturb the airflow which could result in less cooling.

2: Price – another disadvantage of this form factor is the high price. However, you can choose the mATX variant by compromising aesthetics, and RGB LEDs.

What is BTX?

BTX or Balanced Technology eXtended is a form factor of the motherboard that was introduced by Intel in 2004. It was designed to replace the de facto standard – ATX.

Balanced Technology eXtended was introduced to solve major problems that existed in the ATX form factor. The biggest problem that existed was ‘heat’. The ATX’s component arrangement hindered airflow that resulted in less cooling.

When BTX came, the location and design of the components (processor chip, northbridge chip) was altered which made this form factor better than the ATX board in terms of cooling. This became the biggest advantage of BTX over ATX.

However, despite being better than ATX in terms of cooling, people do not prefer this form factor because of the following reasons:

  • People already invested in ATX systems and don’t want to change.
  • BTX is more expensive in comparison to ATX.
  • Most users simply do not care about the cooling factor.

There may be other reasons why people choose ATX rather than BTX. One biggest and obvious reason is that Intel has discontinued the development of the BTX board.

Pros and Cons of BTX

Let us now see what advantages and disadvantages a BTX form factor carries.

Pros:

1: Better airflow – the biggest advantage of the BTX board is that it focuses on airflow and delivers better cooling than ATX.

2: Reduced latency – the design, new component location on the board reduces latency.

3: Stability – Efficient cooling provided by this form factor offers component durability as well as system stability.

Cons:

1: Price – Though BTX offers utilities, it costs more than ATX.

2: No upgrade – Intel has stopped developing this technology. Instead, they focus on reducing the power of the CPU, hence reducing heat and making ATX effective.

Comparison Table between ATX and BTX

To help you grasp the information better, we suggest you have a quick glance at ATX and BTX comparison table.

Features ATX BTX
Full-Form ATX stands for Advanced Technology eXtended BTX stands for Balanced Technology eXtended
Meaning ATX is a form factor of the motherboard which was introduced to replace the standard AT design. BTX is a form factor of the motherboard which was initially designed to replace ATX.
Invented ATX was first introduced in 1995 by Intel. It was introduced in late 2004 and early 2005 by Intel.
Airflow & cooling ATX board design and component location block airflow. Thus, less cooling. BTX solved this problem and has better airflow, hence more cooling.
Input/output Ports On top of the board. Below the board
Current Status De facto standards of the motherboard. Rarely found in PCs

Main Differences between ATX and BTX

In debates, the most common difference between ATX and BTX is regarding the board design and cooling performance which is correct, but here is our answer to this subject:

  • ATX is the successor of AT design and is currently the de facto standard of the motherboard. BTX was initially introduced to replace ATX but couldn’t succeed in doing so.
  • ATX board design and component placement resulted in less airflow and more heat, so BTX was invented to solve this problem. The Balanced Technology eXtended altered the location of the components and created a technology with better airflow and effective cooling.
  • In an ATX motherboard, you will find IO ports on top of the board, whereas in BTX it is situated below the board.
  • BTX board requires special arrangements to maximize the cooling, but in the ATX board, no such arrangement is required.
  • BTX system development is discontinued by Intel, which means it is rarely found in PCs. ATX, which is currently dominating the market is upgradable and is common in PCs.

Conclusion

ATX and BTX are form factors of the motherboard. Balanced Technology eXtended is the advanced version of Advanced Technology eXtended and was introduced to replace it in 2004, nearly after ten years when ATX was invented.

In the BTX board, essential components like the IO ports, slots, memory modules, etc. are situated below the board to maximize the airflow. This makes BTX better than ATX in terms of cooling.

However, only one quality could not simply become the dominating force of the market. Despite providing effective cooling, BTX was and is not preferred by people. In contrast, people prefer the ATX system due to its performance, speed, expansion capabilities, upgrades, etc. and this is why ATX is widely used in PCs in comparison to BTX.

BTX Form Factor PC | Thermally Superior Design That Failed

 

Not much is written these days about the lowly desktop computer. Smartphones, tablets and laptops take center stage. You may disagree, but I believe the desktop is going to be around for a long time. Its relatively low price and super performance numbers can’t be matched in other form factors. Cloud computing that moves processing power to a remote location and continuing advancements in low power performance chips will further erode desktop sales, especially at the low end, but you’re going to have to pry this design from the dead hands of engineers and scientists who demand high-powered local computing. These types of systems are power pigs and even their lower performing counterparts are getting smaller (small form factor desktops), increasing thermal management challenges.

Why didn’t the market embrace a proposed standard in PC architecture design that offered, among other things, substantially improved thermal headroom? Major OEM’s produced it and millions were sold, yet it remains a virtual footnote in PC system design. I’m talking about BTX architecture (motherboard layout and system design).

Since the mid-1990’s the ATX (Advanced Technology Extended) desktop architecture had been king. Power and power densities of CPUs were still relatively low so this Intel design, later adapted to AMD processors, was never meant to address growing thermal challenges. In those days, Pentium II and III processors were still in the 20-40 watt power range with power densities in the low to high teens (Figure 1).

Figure 1: CPU Power Density (Source: Canturk Isci, Workload Adaptive Power Management)

As you can see in Figure 2 (excuse my crude airflow drawings), a typical ATX layout positioned the CPU toward the rear of the machine with a single 100mm exhaust fan used to move air through the system. When necessary, a small fan was added on top of the CPU heat sink for further cooling but it distributed warm air throughout the system. Cool inlet air was impeded by forward connectors and memory modules that were perpendicular to, and positioned in front of, the CPU. Graphics cards where designed so that heat sink and associated fan faced toward the bottom of the case. From a thermal management standpoint, this design was marginal but adequate for the time.

Figure 2: Typical ATX Architecture

The long lived Pentium IV, with its’ every increasing power (80-115 watts in later iterations) and power densities (roughly 60-90 w/cm2), forced Intel to rethink ATX architecture and in 2003 it pushed a competing architecture whose primary purpose was better thermal management. The idea was simple. Give the CPU ample cool air and place all component in-line with the air flow.

Figure 3: Sample BTX Architecture

Figure 3 shows the first mass produced BTX design from Gateway (2004). Dell followed with a similar design the next year and HP as well as a few others soon got on board. The CPU was moved to the front of the machine where it could benefit from the coolest air. Rear exhaust fan diameter was generally increased to 120mm and in some cases (shown) at additional 120mm intake fan was added. A shroud was sometimes used to direct intake air over the CPU and move it in a straight line toward the exhaust fan. Additionally memory slots where positioned parallel to air flow and the motherboard was moved to the other side of the case. This allowed graphics cards to be flipped upside-down so the GPU fan received additional air and could more easily direct it toward the exhaust fan. Finally, there existed a thermally efficient desktop system design. Yes it was marginally more expensive – on the order of $10-$15 with larger fans and shrouding in addition to a non-standard layout – but the thermal benefit seemed to outweigh the cost premium.

Engineers are often asked to tackle thermal challenges after system layout is locked. I know it’s not best practice, but it happens more than we’d like to admit. BTX gave us a better platform to manage heat, but it failed despite the fact that the latest generation of desktop processors (Core i7) still has power densities considerably higher than their Pentium III counterparts.

So why did BTX fail to replace an aging ATX design? We’d like to hear your comments.

Please contact us if you’d like to learn more about how Celsia can help with your next heat sink project. We’ve worked on everything from consumer devices to industrial test equipment that require heat sinks to cool anywhere from a few watts to a few kilowatts.

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BTX form factor: a new concept for CPU cooling

While the specifications for the BTX form factor were
announced back in September last year, many users were worried about the need to migrate to a new standard for cases and motherboards. The analogy with the history of the introduction of ATX did not give rest to many — the process of changing standards was painless only for the most wealthy users who were able to immediately change the entire computer. Subsequently, it gradually became clear that BTX would not be so categorical — ATX power supplies could be installed in full-size BTX cases, and the process of changing form factors would take three years.

Nevertheless, already in the second half of the year, Intel and its most loyal supporters will begin to impose new BTX-style solutions on the population. It is assumed that OEMs will be the first to switch to BTX, and Intel itself will start producing the corresponding boards. Other brands will wait a little bit with the transition to BTX, implementing it only in their most expensive and advanced products.

Our colleagues on the site TweakTown posted a very instructive story about some of the features of the constructive side of the BTX form factor. First of all, they consider in detail the principle of the so-called thermal module, which in BTX cases will be responsible for the lion’s share of the work of cooling components.


Unfortunately, so far the story is mostly about «lying» BTX cases of the Desktop type. It is clear that in the OEM version they are very common, but in the do-it-yourself (DIY) segment, vertical «towers» are more popular. However, the general principles of the cooling system can be understood.

One large fan draws air from the front of the chassis through a closely spaced processor heatsink. Air leaks are eliminated through the use of a special casing with a vibration-isolating gasket.


Take a look at the heatsink — it is very similar to the concept used by Gigabyte engineers to create their recent miracle called 3D Cooler-Pro. We hope that the heatsink will effectively remove heat, because fresh processors on the Prescott core heat up quite noticeably, and at frequencies above 3.8 GHz they generally require the most powerful cooling. For LGA 775 processors at 3.6-3.8 GHz «everything is only just beginning», so the cooling efficiency must be indisputable.

Then the air passes into the case, blowing over the video card and other expansion cards, as well as memory modules. The heated air will exit the case around the rear panel as usual. In the diagram, the areas with the highest airflow speed are highlighted in red, the areas with the lowest airflow speed are marked in blue.


It’s hard to say whether the idea of ​​»co-cooling» all the hottest components from a single source of cold air will justify itself, but in larger MidiTower class systems, the number of fans will probably have to be increased.

By the way, BTX motherboards will start to get rid of legacy I/O ports this year. Serial and parallel ports will disappear from the rear panel, even PS / 2 jacks will give way to USB ports. But the latter will be in abundance — two to three times more than on modern motherboards. Most chipsets this year will support up to eight USB 2.0 ports, some up to ten. Of course, all sorts of exotic connectors such as WiFi, Bluetooth will take advantage of the situation to no lesser extent :).

We hasten to reassure you — not all motherboard manufacturers will renounce legacy ports so decisively. During this year, PS/2 and even serial and parallel ports will be available on most boards.

The situation with power supplies is quite simple: full-size BTX cases will be able to work with existing ATX units, as long as they meet the power requirements of the equipment. Small-sized BTX cases will be equipped with special power supplies, in which solutions of the previous type will no longer fit.

recommendations

The most rapid transition to BTX for the Intel platform will be the fastest, since this company is promoting this standard. And yet, the industry will be able to completely abandon ATX only by 2006-2007.

The New Standard in Computer Cases in Action / Chassis, PSU & Cooling

Author: Andrey Chumichev

Testing the AOpen B300A case

Cases of the BTX standard (Balanced Technology Extended) will sooner or later force out the old ATX cases from the market. This process, of course, will not be easy, and will most likely drag on for more than one year, but there is no doubt that sooner or later the new format will still supplant the old one. As an example, we can recall the story of the introduction of the current ATX standard — at first, many were scared off by prices, novelty, cases of the old AT format did not want to give up their positions for a long time, at one time even motherboards were produced that provided the ability to power both AT and ATX standard. However, one way or another, today almost every office and home has ATX cases — the advantages of the standard over the ancient AT are obvious.

In principle, the advantages of BTX standard cases over the current ATX cases are no less obvious in theory. It is known that the development of a new chassis standard (one of the initiators of this was Intel) was prompted by the constantly growing power consumption and heat dissipation of computer components (primarily, of course, this concerns the central processor and, to some extent, the video card). Accordingly, BTX standard cases were originally developed taking into account the increased requirements for power and cooling of computer components. This means that these solutions must be more efficient in terms of component placement, have better cooling capabilities and a well-thought-out ventilation scheme.

The BTX standard originally provided for three chassis and motherboard form factors: pico-BTX, micro-BTX, and full-sized BTX, or BTX-tower. All of them have their own advantages over their counterparts from the traditional ATX camp, providing a high density of mounting components, coupled with efficient cooling, differing, as the names suggest, in size (and, of course, in the power of the power supplies installed in them).

First glance

Life often shows that technologies that have a lot of advantages in theory turn out to be much less attractive in practice. Won’t the same happen to BTX cases? The answer to this question can be obtained only by «touching» not a printout with the requirements of the standard, but a real sample of the case manufactured according to this standard. We tested the AOpen B300A case, one of the first BTX cases, in real life.

So, AOpen B300A itself is a BTX standard case, to be more precise — Desktop BTX format, or Slim BTX. Its dimensions are noticeably smaller than those of its predecessors from the Desktop ATX camp.

The front panel is made of black plastic, it looks neat and attractive, structurally it is a single unit with the housing cover. Audio, USB and IEEE 1394 connectors are provided, which is very convenient. Not all ATX cases provide these connectors to the front panel, which makes it difficult to connect peripherals: in order to connect, for example, a USB flash drive, you have to look for approaches to the back of the case, and this is not always possible. The only noticed drawback of the front panel is the dim glow of the Power LED, it is quite difficult to understand whether it glows or not.

The interior «decoration» of the case also turned out to be very well thought out. The hard drive and another 3. 5″ device (it can be, for example, a floppy drive or a card reader) are installed in a basket that is attached directly to the case.

Installation of a 5.25″ device (most likely it will be an optical drive) is carried out in a special folding «pocket» that is attached to the frame of the case on hinges. When assembling a computer, it can be folded to the side so that it does not interfere with the installation of others components.

It’s nice that the 3.5″ and 5.25″ devices are mounted in their compartments using special slides, so you don’t have to fiddle with screws and a screwdriver.

The motherboard is screwed directly to the bottom of the chassis. It is also worth paying attention to a fundamentally new design of the cooling device for the central processor. The radiator is a hollow copper rod with an aluminum spiral wound around it, it is blown by a fan. Structurally, the cooling device is completely different from those that we are used to seeing in ATX cases.

The BTX is specified to mount directly to the bottom of the hull. Nevertheless, this design does a better job of cooling the processor than conventional solutions for ATX cases. Test results also speak about its effectiveness (more on that below).

This chassis accepts only low-profile expansion cards, with the exception of one card, which may be a full-size expansion card. It is installed in the PCI-Express slot through an adapter (riser). In our case, it was a full-sized graphics adapter.

In general, the complete system gives the impression of a solid, tightly packed construction.

Power supply

However, as you know, not only the quality and thoughtfulness of the chassis itself is important, but also the characteristics of the power supply installed in the case. And here you can be relatively calm: in this rather miniature case, the FSP 275-50BW power supply is installed. Power supplies from Fortron Source have always been considered high-quality products, time-tested and successful in our Russian power grids that do not shine with power quality.

PSU characteristics are as follows:

Power:

Max. current:

+3.3V

13 A

maximum — 275 W

+5V

14.5 A

max. total on channels + 3.3 V and + 5 V — 110 W

+12 V (1)

5 A

+12 V (2)

13.5 A

-12 V

0. 3 A

+5V SB

2 A

Hard to learn, easy to fight?

Test configuration:

  • Motherboard Intel D915GMH Socket 775
  • Intel Pentium 4 550 3.4 GHz Socket 775
  • Memory module 512 MB DDR400 Kingston — 2 pcs.
  • Seagate HDD ST3120827AS
  • Video adapter Sapphire Radeon X600XT 128 MB DDR-128 bit
  • Drive 3.5″
  • DVD-RW Teac DV-512G
  • BTX AOpen B300A Chassis with 275W PSU

Software used in testing:

  • Windows XP Professional SP2
  • ATI Catalyst video driver v.4.11
  • Intel INF update v.6.1.0.1008
  • S&M v.1.3.0 alpha — utility for testing CPU/cache/memory subsystem
  • Intel IOMeter — utility for testing the performance of the disk subsystem
  • Futuremark® 3DMark03 v. 3.4.0 — video adapter test
  • SpeedFan v.4.19 — utility for monitoring system status (temperature, fan speed, voltage)

System load in extreme modes was achieved by simultaneous launch of S&M, IOMeter and 3DMark 03 programs. System status was monitored by SpeedFan program. The test results are shown in the form of screenshots.,

Processor, HDD, and motherboard temperature curves over time

Change in CPU fan speed over time

As you can see, the CPU temperature slowly rises to 50C° after the system is turned on. At the same time, the average fan speed is less than 600 rpm (with no load on the processor). After running the tests, the processor temperature rises sharply to 63-65C°, no further growth occurs, because the processor fan speed increases sharply (up to 1800 rpm, sometimes even up to 2000). The rise in motherboard temperatures accelerates at the beginning, but then the temperatures stabilize at 49C° (System zone 1, the temperature is measured under the CPU socket) and 39C° (System zone 2, the temperature is measured near the memory modules).

Hard disk temperature under heavy load does not exceed 39-40C°, and the temperature of the video adapter does not exceed 61C°.

Temperature curve at the end of the test

Fan speed curve at the end of the test

When the system components were unloaded, the processor temperature dropped to 48C°, then slowly rose to 60C° and stabilized. The motherboard temperatures in zones 1 and 2 also dropped, then stabilized at 46C° and 40C°, respectively. The processor fan, when the temperature drops, also sharply reduces the speed from 1700 to 500 rpm, then the rotation speed rises to 700-900 rpm.

Conclusions

To begin with — about the state of the power supply, as the most important component responsible for the «health» of the entire computer as a whole. Of course, we checked the voltage ratings issued by the power supply under load. It is gratifying that during testing they practically remained unchanged, with the exception of the voltage of 12 V, which decreased slightly (by 0.08 V) at 100% processor load. The decrease in this channel is quite within the acceptable limits, and in itself it is not surprising — after all, here the central processor is the main consumer of electricity. Conclusion: FSP 275-50BW is a very high quality power supply, its use is more than justified. Especially taking into account the fact that the case is still small-sized, and it is unlikely that anyone will install top-end video accelerators with terrifying power consumption or SCSI raid arrays in it. And for a system with an average video adapter and a Pentium 4 processor, this PSU is more than enough power.

Well, and the most important conclusion: one of the first «pancakes» of the BTX format came out by no means lumpy. The AOpen B300A desktop BTX case, despite the significantly higher mounting density compared to the ATX form factor and the absence of additional fans and air ducts in the case, provides sufficient cooling for all system components.