btx form factor flawed?

jihiggs

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Oct 11, 2001
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it seems to me the new design for the btx form has a major oversight. not that big of a deal really but could prove quite annoying. obviously this wont make sence if you havent seen the design so here is a link. <A HREF="http://www.anandtech.com/showdoc.html?i=1876 " target="_new">http://www.anandtech.com/showdoc.html?i=1876 </A>
the first thing i noticed is the whole board is flipped around. to get to the board you have to open the right side of the case instead of the left side. that in itself seems annoying to me just cause ive been used to the left side being the business end all this time. if that werent enough they stuck the cpu right where the hard drive cage should be! in the cases shown in the link they simply dont have a drive cage there. this will make it very difficult to arrange 4 or more hard drives. sure they could put them some where else in the case but then you would need to have a fan in that other place just for the hard drives. granted hard drives dont get that warm but you need at least a fan moving over them, especialy the raptors.

this is my boomstick!<P ID="edit"><FONT SIZE=-1><EM>Edited by jihiggs on 12/15/04 10:12 AM.</EM></FONT></P>
 

slvr_phoenix

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(Your link is broken by a space being included at the beginning.)

You know, until you pointed it out, I never even noticed that a BTX chassis opens up on the right instead of the left. :\ Silly to change that, but then I guess that makes it pretty clear not to try to use an ATX mobo in a BTX case and such.

That aside, I'm not sure if I follow your hard drive problem. I'm sure that there will be plenty of cases that will be tall enough to provide room for four hard drives. Typical users don't even have two hard drives, so I can understand typical cases not having room for them. Power users just have to power shop for their case is all.

What I really don't like about the BTX standard is that it turns the power supply into an exuast fan for the CD drives only. The CPU is cooled in a completely seperate channel now. That's kind of messy and may annoy major OEMs. Then again, it may not.

Just as (or even more?) messy is that the graphics card is now placed in the wash of the CPU's exhausted heat. :O Those funky enclosed intake/exhaust channel systems on graphics cards that work solely through the back panel instead of intaking air from inside of the case are going to suddenly make a lot more sense as no graphics card is going to want their air intake to come from the CPU!

The BTX form factor really only makes sense from an Intel perspective. Most of their customers are major OEMs building cute little boxes where the CPUs run hot, the graphics are handled onboard, there are hardly ever PCI cards to worry about, and there's typically only one hard drive that doesn't need any special cooling.

Because the BTX factor seems so bad for hot hard drives, for hard drives arrays, for high-end graphics cards, and well, for enthusiasts in general, I expect that there will be enough of a resistance to the uptake of BTX that either something will be changed, ATX will always be available, or case manufacturers will be working on unofficial standards to solve these problems. If not then Intel enthusiasts are going to have a very rough time. **LOL**

I wonder if AMD will even bother looking at the BTX standard at all, as they tend to cater to enthusiasts (and now to workstation/server markets) where people will laugh (or cringe) at BTX.

<pre><b><font color=red>"Build a man a fire and he's warm for the rest of the evening.
Set a man on fire and he's warm for the rest of his life." - Steve Taylor</font color=red></b></pre><p>
 

jihiggs

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Oct 11, 2001
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well, most cases have a hard drive chasis that extends from the 5 1/4 rack down to the bottom of the case. most enermax cases do that anyway and i think antec also. this doesnt leave much room between the hard drives and a fat heatsink sitting right next to the connectors. i think the cases would have to be a good 2 inches deeper just for the thing to fit like it does now because most hard drives hang over the motherboard anyway.

this is my boomstick!
 

endyen

Splendid
I have always thought that the concept of "heat channels" was good, but BTX is not very practical. If intel could change the law about heat rising, then front to back heat channels might work. But then again, Intel never seems to go with the flow anyhow.
 

Crashman

Polypheme
Former Staff
You can't have it both ways! Either the top of the board faces the left side of the case (open the left side to insert cards) with the CPU at the bottom (blocking the traditional hard drive location), or the top of the board faces the right, with the CPU on top.

My logic tells me the first scenario is correct for most cases: The board mounts in a traditional style case, with a different back panel (ports now on the bottom).

The tower example used is an exception, putting the CPU at the top, violating Intel's straight-path thermal design.

<font color=blue>Only a place as big as the internet could be home to a hero as big as Crashman!</font color=blue>
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slvr_phoenix

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well, most cases have a hard drive chasis that extends from the 5 1/4 rack down to the bottom of the case. most enermax cases do that anyway and i think antec also. this doesnt leave much room between the hard drives and a fat heatsink sitting right next to the connectors. i think the cases would have to be a good 2 inches deeper just for the thing to fit like it does now because most hard drives hang over the motherboard anyway.
But my point is that as far as Intel is concerned, <i>most</i> people only have one hard drive anyway, and Intel left plenty of space for even <i>two</i> hard drives. Wow. Intel is so good to us.

Seriously, there will always be manufacturers of various products willing to ignore Intel. So just don't buy BTX, or carefully shop for a case that meets your needs if you do. :)

Hopefully the industry will get the idea that BTX is stupid for enthusiasts and BTX will just become an OEM niche at most.

<pre><b><font color=red>"Build a man a fire and he's warm for the rest of the evening.
Set a man on fire and he's warm for the rest of his life." - Steve Taylor</font color=red></b></pre><p>
 

jihiggs

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Oct 11, 2001
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but if its the standard that will replace atx like atx replaced at, we wont have a choice! sure you could use an atx case still but if no new boards are being made to support atx your screwed! is this design just somthing intel wants and is forcing oems to do?

this is my boomstick!
 

slvr_phoenix

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Dec 31, 2007
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but if its the standard that will replace atx like atx replaced at, we wont have a choice! sure you could use an atx case still but if no new boards are being made to support atx your screwed!
1) There are considerable differences this time around. Not the least of which is that this time AMD has some clout and a reason to object to BTX as a standard. (They still may not, but they easily could hold up the standard's uptake if they chose to do so.)

2) Buy a foot taller case with room for four hard drives. Bigger is better anyway. :)

is this design just somthing intel wants and is forcing oems to do?
That's SOP for Intel. With them when is that ever <i>not</i> the way? ;)

<pre><b><font color=red>"Build a man a fire and he's warm for the rest of the evening.
Set a man on fire and he's warm for the rest of his life." - Steve Taylor</font color=red></b></pre><p>
 

jim552

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I concur.

I find this to be a rather annoying bunch of changes.

I do think it is obvious through from the choices that Intel has made that they have "given up" on the possibility of actually lowering their thermal output. (Maybe it is indeed not possible anymore given what we expect from CPU's.)

They have moved the CPU to the front "coolest" portion of the case, so that it can be cooled the best/easiest.

As a result other "conventions" that we were used to have been sacraficed. (NOTE: We can "at least" be thankful they didn't change the standard connector types. Since that article mentioned that, I am supposing they were on the table as well.)

I wonder if anyone noticed, or mentioned, that the point chosen will become the "dirtiest" point as well. This may become a problem for cooling since the heatsink will be exposed to incoming "dirty air" first rather than other board components. (Ever open up a CPU case, and notice the dirt accumulating along the airflow path?)

I am taking this as a sign that the next version of Pentiums are going to be MUCH warmer than the current crop.

Maybe on this bunch the whole joke about "not needing a heater at home" won't be a joke anymore?

Oh well.

I am "completely" AMD for Desktops and Servers! Hopefully they won't buy into this anytime soo and upset "My Apple Cart of Systems"?
 

The_I

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Oct 15, 2003
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I disagree.

It's a bad argument about the drive cages: you don't get less space in btx, the space is used differently. In a normal atx tower you may have drive-cages all the way from top to buttom, but if you were to actualy put harddrives into them you'd not get any air into the case at all, if you were to have decent cooling you'd have to remove a couple of harddrives anyway. The only thing btx does, as far as I can see, is forcing you to keep an uncluttered airintake in the front of the computer.

About the gfx-card being getting the hot air from the cpu: as far as I can see this is a pretty rational way to do things. You just have to see the cooler cooling the cpu as a cooler for the gfx-card as well, if sufficient amounds of air is going through the cpu heatsink it won't become that hot, and the gfx-card will benifit from a pretty focused airstream. In an atx-case you could argue the same thing, that the warm air from the gfx-card rises to warm up the cpu, and the hot air from the cpu goes into the psu, it's not a problem when there's enough airflow. As far as I know you could say the same about a water-cooled system, here everything is connected in series as well.

As far as I can see btx simplifies the airflow pattern a lot. There's no cpu fan blowing air towards the mainboard and creating turbulence, you have it all nice and clean with a single big intake fan. The only problem I can see is convection, which one ought to be able to account for in some way.
 

jihiggs

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just because you have hard drives in front of a fan doesnt cut down the ammount of air the fan can move. it will just go around the hard drives. another advantage of having the drive cage go all the way down to the bottom is space in between the drives. theres nothing in the btx standard that says the drive cage cant go down to the bottom, there just isnt much room between the hard drives and the cpu that way. that means you have to have ribbon cables and whatnot right around the heatsink. and what do you mean no cpu fan with the btx standard? i dont see anything that says there is no cpu fan with the btx standard. one case fan 5 inches from the heatsink isnt going to do a very good job unless it was specificaly designed for the btx standard. i guess they could use some channel box or somthing from the case fan to the hsf but whats the point, oems have been doing that for years anyway.

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slvr_phoenix

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It's a bad argument about the drive cages: you don't get less space in btx, the space is used differently.
But it is the difference in how the space is used that matters. Before there was a nice clean column for hard drives that often would have an intake fan in front of the drives which cooled them off. Now you have no intake fan for your hard drive and a lot of wasted space past the CPU.
Well, I suppose that you could use that space past the CPU for more hard drives, and you could even add an intake fan there. But that would still leave two seperate blocks of hard drives <i>and</i> one block would have cables running past the CPU. At its best it is still a very messy way to do it.

In a normal atx tower you may have drive-cages all the way from top to buttom, but if you were to actualy put harddrives into them you'd not get any air into the case at all
You obviously haven't seen a modern ATX case then. The new method (that works great by the way) is to mount the hard drives sideways instead of front to back in nice convenient trays that have plenty of space between them for air. You couldn't do that at all with the BTX format because you wouldn't have enough space.

But even with the old ATX hard drive mounting method there was still plenty of air moving around the hard drives even if you stacked them in like sardines. The air holes that the air comes in through the front panel are usually more restrictive than a bunch of hard drives stacked closely together.

The only thing btx does, as far as I can see, is forcing you to keep an uncluttered airintake in the front of the computer.
The <i>only <b>good</b> thing</i> you mean. There are plenty of bad things that it does just to fix that one flaw, which Intel had already fixed in their 3GHz qualification standard anyway.

About the gfx-card being getting the hot air from the cpu: as far as I can see this is a pretty rational way to do things. You just have to see the cooler cooling the cpu as a cooler for the gfx-card as well
I'm sure glad that I don't see with your eyes then, because besides being untrue, that's a really bad way to see it.

In ATX you typically have a front intake mounted near the bottom. The air from this is at most polluted by hard drives. It <i>was</i> this air that cooled the graphics card. So what if some of the air from the graphics card made it to the CPU. The CPU has the most room for a heatsink so it could easily take the few extra degrees.

In BTX you now have your graphics card's air polluted by the <i>hottest</i> device in your computer. A lot of graphics cards have only tiny passive heatsinks. The more powerful ones have small heatsink/fan combos that have to fit in that tiny space between the AGP slot and the PCI slot. Only in extreme cases do the heatsinks on graphics cards go larger than that. So all of that extra heat from the CPU is now pushed onto the graphics card with a very limiting factor for its heatsink size. A lot of graphics cards aren't going to be able to take the heat of a 4GHz Prescott (or worse, multi-cored CPUs) no matter what you do.

if sufficient amounds of air is going through the cpu heatsink it won't become that hot
So your solution to a failing graphics card because of the heat from the CPU in the BTX format is to install the highest CFM fans you can find and turn your PC into blow drier that makes enough noise to rival a jet airplane?

In an atx-case you could argue the same thing, that the warm air from the gfx-card rises to warm up the cpu, and the hot air from the cpu goes into the psu, it's not a problem when there's enough airflow
It's not about airflow. It's about the space available for heatsinks in the order of the air pollution. There are efficient ways to order things, and then there is the BTX format.

As far as I know you could say the same about a water-cooled system, here everything is connected in series as well.
A water cooling system has several differences. First of all every water cooling system that I've specced (that hasn't been for the CPU only) has never set up a serial flow (where the heat from one device is passed on to the next). I've always split the cold flow in parallel and joined it up again right before the pump.

Secondly, watercooling systems don't have nearly the size constraints on their waterblocks that aircooling systems have on their heatsinks.

And thirdly, BTX actually looks really bad for designing a watercooling system around, now that I look at it. :\

As far as I can see btx simplifies the airflow pattern a lot.
This is the one thing that I agree with you on here. Simple however is not always <i>better</i>, and that is the problem.

There's no cpu fan blowing air towards the mainboard and creating turbulence, you have it all nice and clean with a single big intake fan.
Can I see where you got <i>that</i> information from? Because as far as I know the CPU still has the exact same heatsink <i>with</i> fan in BTX.

<pre><b><font color=red>"Build a man a fire and he's warm for the rest of the evening.
Set a man on fire and he's warm for the rest of his life." - Steve Taylor</font color=red></b></pre><p>