Intel's Long Awaited BTX Form Factor
by Purav Sanghani on November 15, 2004 5:31 AM EST- Posted in
- Cases/Cooling/PSUs
Examining ATX
The ATX form factor was designed by Intel back in 1995 to improve on the AT form factor. It brought about changes that would help standardize placements with various types of hardware, one being full length expansion cards; in original AT layouts the processor sockets were positioned at the front of the motherboard which kept full length expansion cards from being used. Now that the ATX form moved the CPU sockets to the back right corner of the motherboard full length PCI/ISA cards had plenty of room.AT also had the problem with drive bay interference since the AT motherboards were longer from front to back. With ATX the motherboard is cut wider, instead, to provide some clearance between drive bays and the board itself. Moving the CPU socket also aided in this change since there was a need for board space at the back right instead of the front left corner of the motherboard.
Some of the other changes from AT to ATX:
- Power supply connection AT motherboards used dual 6-pin connectors to power the system which was confusing and also potentially dangerous if we did not know what went where. The ATX specification implements a single 20-pin connection from the power supply to motherboard to eliminate confusion and damage to hardware.
- Power management The older AT specification also had the power button of the case hard wired directly to the power supply. The ATX specification implements the "Soft Power" feature which allows the motherboard to turn the power supply on and off by software. For example, when shutting down the Windows OS in an AT set up the system needed to be manually shut down by pressing the power button. The ATX form factor allowed the system to be automatically powered down after the OS logged off.
- Integrated I/O, peripheral connections On older AT boards, instead of having the parallel and COM ports we see at the back of the motherboards, extra cables were required to extend those features to the case. We needed to run cables from pin headers on the motherboards and mount them to the cases to be able to connect printers or other devices that used these ports. When the ATX form factor was introduced, these connectors were soldered directly on to the motherboard to both reduce the time to install components and the overall cost of a system, as well as to increase the reliability of the ports.
- Cooling and air flow Moving the CPU to the back right of the case closer to the power supply and the backside fans had a positive effect on cooling. Warm air created by the CPU would be pulled out through the back of the case as well as up through the power supply if it had a fan facing the CPU.
The ATX had a clear goal in mind; a new design that would reduce clutter, standardize component design and bring more control to the motherboard. The BTX mandate is a little less clear; reduce the PC footprint while more efficiently cooling the components. Keep this mandate in mind as it plays heavily on our conclusion.
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trikster2 - Tuesday, November 16, 2004 - link
I've got to say, this review is bad, even by anandtech standards.
Comparing an mBTX destop to a mATX TOWER to a Fullsize ATX desktop, litteraly comparing apples to oranges to pears, and then coming to sweeping conclusions like "any of us were skeptical for a long time, but after seeing the numbers ... we can conclude that BTX is not hype. " is simply ludicrouse.
Shame on you anand for letting such a review fall through your QC into the hands of the general public.
I'm not sure if you guys are incompetent or payed by intel to find a combo to pimp the BTX standard. I just did a refresh 5 times, no intel adds so it must be the former.
How about spending 49.95 on a decent desktop mATX case and compare apples to apples, instead of just grabbing whatever was laying around the lab (we've seen that whacked oppus case in other reviews haven't we?)?
I have the silverstonetek equivalent of the oppus matx tower. It is the worst mATX cases I have ever worked with. Give us a break and do a valid review, mATX single fan 1/2 height desktop to mBTX single fan 1/2 height desktop.
johnsonx - Tuesday, November 16, 2004 - link
I see nothing here in the BTX standard that couldn't have been better accomplished with a backwards and forwards compatible ATX II standard.ATX II compliant motherboards would have standardized locations for the CPU socket, two standard locatations for RAM (either or both locations could be used, as needed), standard locations for the power connectors, standard locations for the most common onboard ports (IDE, SATA, front USB, audio, etc.) and standard component heights (capacitors and etc.).
ATX II compliant cases would have standardized air intake and exhaust locations, fan mounts, and ducting. ATX II cases could be built to open from the right side, with the CPU on the bottom. The ducting would be removeable for use with a legacy ATX mainboard.
ATX II compliant heatsinks would be fanless, designed to be cooled by an ATX II chassis duct, but would have a fan mounting point for use in a legacy ATX chassis. Boxed coolers that come with retail CPU's would include the fan on a standard clip with instructions to remove it when used with an ATX II compliant chassis and mainboard.
ATX II compliant power supplies would basically be the same as the latest ATX supplies are now - 24pin power, 8-pin ATX 12v power, standard 4-pin drive power plugs, SATA power plugs, PCI-E graphics power plug. 24 to 20 pin converters and 8-pin to 4-pin converters would be standard with retail power supplies.
Any mix of ATX and ATX II components would work fine together, but a system built of all ATX II components would gain various cooling, noise level, assembly and operational advantages.
What does BTX offer that my hypothetical ATX II standard doesn't? Oh, yeah... ATX II couldn't give you a face of hot air...
xsilver - Monday, November 15, 2004 - link
To the guy b4 that was wondering where the air intakes are -- no amount of case fans are going to create a vacum inside your case, there's just not enough pressure -- unless you tape up all the gaps lol.... so the air will just "flow" in from any holes in your caseblackmetalegg - Monday, November 15, 2004 - link
Bah we're(work) using this motherboard in an application that shall remain anonymous(NOT oridinary PC) and the damn design make wiring a bitch to deal with. And the motherboard isn't all that stable, considering it's from Intel...justly - Monday, November 15, 2004 - link
BTW that 20.666715 "cfm" is assuming all of the area taken by the 2 fans has air flow, but we should all knoe that the motor and frame ocupy some of that space so the actual "cfm" would be lower.justly - Monday, November 15, 2004 - link
Why was "lfm" not converted to "cfm" for a direct comparison on page 11?If I am reading this correctly the BTX provides 40 "cfm" while the ATX requires 150 "lfm". This sounds like BTX is an overwhelming success, untill you do the conversion that is. So what exactly does this 150 "lfm mean in comparison, well if the ATX uses 2-80mm fans that would be 80mm x 80mm = 6400 square mm per fan, 6400 x 2 = 12800 square mm for both fans, convert that to square ft and you get 0.1377781 square ft, take that and multiply by the 150 "lfm" and we get (drum roll) 20.666715 "cfm". Thats right about half what the BTX has.
I don't know if this was intentional or not, but I will give the author the benifit of the doubt and assume it was not.
If I have overlooked something please explain my mistake, if not then I feel some injustice has been done to the readers that did not ask this question.
ShadowVlican - Monday, November 15, 2004 - link
like someone else said... the BTX form wasn't made for enthusiasts, since we already know how to cool our rigs properly..BTX is for the average consumer who doesn't know jack about computers, so BTX will help those people have quieter/cooler computers without them reading forums/articles
i'm just wondering how well the transition from ATX machines into BTX will go...
ZobarStyl - Monday, November 15, 2004 - link
Yes Five40, you can't directly upgrade from 754 to 939, but you can take your case and PSU with you...I'm using the same case I used in my AXP system now for an A64 with watercooling, but if Intel has their way, my next rig won't be able to use the same rig and I'll just have to spend more cash. Hence, we are rightfully pissed because the real question is "Why?" and when something lacks benefits but costs you mad cash: a whole new case and good PSU will set me back 120 bucks, for what? Nothing worth my time.MAValpha - Monday, November 15, 2004 - link
Anyone know how pBTX stacks up against FlexATX?five40 - Monday, November 15, 2004 - link
#50....umm I can't do a A64 to A64 upgrade so what's your point? 754 to 939 does me no good. I just see this as another socket update. A64 might not need it right now, but if all things where just made for what we need right now, we'll move forward at a very slow pace.