A7V400-MX SE w. 400MHz FSB but no PC3200 support?

[TheSatori]

Greetings,

I bought the ASUS A7V400-MX SE motherboard a while back because I wanted to migrate most of my hardware into a smaller and more silent case without loss of performance. Here's what I had in my old box:
[*:c2c1c781c7]AMD Athlon XP 3200+[*:c2c1c781c7]2x Nanya Elixir 1GB PC3200CL3 (product nr.: M2U1G64DS8HB1G-5T)*[*:c2c1c781c7]Gigabyte GeForce 6800 128MB (product nr.: GV-N68128DH)[*:c2c1c781c7]DVD burner, PSU, etc etc.
*: I had 2x Corsair XMS 512MB PC3200CL2 (dual) RAM the last time I was fiddling with this issue, and changed to the Nanya ones later.

This is now all sitting in a Lian-Li PC-42 Micro-ATX Case of doom along with a shiny fan controller 😛

This motherboard seemed the right way to go, as it boasted a 400MHz FSB. Naive as I was, I figured "hey, then it must run my Corsair PC3200 blocks at full capacity". Then, when reading the manual, I notice that it "supports" DDR400 RAM... but it was marked with a star, which lead to the following line:

* You can install a DDR400 DIMM(s) on the slot(s). However, a DDR400 DIMM may only run a speeds of up to 333 MHz (DDR333)

Great. So, you can, but it won't do you any good. Ha ha ha, very funny. I am deeply amused.

I then just thought "well, at least it works", and didn't try any further, but this issue has been nagging me ever since. The FSB supports bandwidth of 400 (200) MHz (it must, the specification says so). But something prevents the motherboard from using this full bandwidth, so any DDR400 RAM is clocked down to a DDR333 RAM (w. 333 (166) MHz FSB).

So, the question is this: what is preventing the A7V400-MX SE motherboard from supporting PC3200 (DDR 400) RAM? Do I simply reconfigure / update my BIOS? If not, then can't I force it to use the full FSB bandwidth? What's the risk? Is it wise? Can I make it wiser (that is, can I prevent short circuiting / overheating)? If this is all hopeless, then is there any advantage of only running 333 (166) MHz FSB on a bus supporting a bandwidth of 400 (200) MHz? (in other words, is there any way for me to feel good about this, or should I live in ultimate shame where a bastard chinaguy from Asus haunts me in my dreams rubbing this futile matter in my face and laughing at it?)

Thank you for reading
TheSatori.

 

[ivan_lee05]

because AMD's Socket-A {464-Pins} does only support maximum of DDR333 or 2x166mhz memories..

and it does not support dual chanelling =)

it does not prevent your memories bandwidth

when a DDR400 3200GB/s clock down to DDR333 it will used DDR333's bandwidth which is 2700GB/s.

or a DDR400 3200GB/s down clock to DDR266 = 2100GB/s

 

[TheSatori]

Well, before switching to the A7V400-MX SE motherboard, I had an A7N8X-E Deluxe motherboard (a wonderful little thing), and with it, the computer was running with an FSB of 400 (200) MHz --- and the RAM was running in dual-channel mode (yarr).

A little something to support my claim:

This is an image from this review introducing the capabilities of the Athlon XP 3200+. And according to AMD's website, both the Athlon XP 3000+ and the Athlon XP 3200+ have an FSB of 400 (200) MHz.

However, this review on the 3000+ states otherwise... while this page in the 3200+ review supports my claim. I believe I will trust the 3200+ review, as the 3200+ wasn't launched during the 3000+ review's making (I think).

And the A7N8X-E Deluxe has a Socket-A. So, the socket shouldn't be a hindrance. I would be more inclined to believe that the chipset doesn't support the full 400 (200) MHz FSB, but then looking at the VIA KM400A specification on the VIA website, it says that the chipset supports the full 400 (200) MHz, as well as memory in dual-channel mode. There's nothing indicating the lack of this support.

Why do I hear that circus-melody in the distance...? 😛

 

[TheSatori]

*sneak, push, nudges the topic a little*

The original question: what is preventing the A7V400-MX SE motherboard from supporting PC3200 (DDR 400) RAM?.

Hypotheses: It is not:
[*:c401253820]The Memory --- they are PC3200[*:c401253820]The CPU --- according to specification, it supports a FSB of 400 (200) MHz[*:c401253820]The Socket --- I had an A7N8X-E Deluxe with Socket A which ran the same CPU and RAM w. a FSB of 400 (200) MHz[*:c401253820]The Chipset --- according to specification, it supports a FSB of 400 (200) MHz
What's left?

Facts? Ideas? Speculation? A "beats me" reply wouldn't hurt either --- would give me a more firm ground on bugging the Asus folks with this matter 😛

 

[4745454b]

The memory controller is on the Chipset/northbridge for the Socket A/462. Its not on the CPU. For the record, there were two 3000+ released. One ran on a 333/166MHz FSB, while the other ran on a 400/200MHz bus. There were also two version of the KT400. The first KT400 ran so bad at 200MHz FSB, that Via had to release the KT400a. This had better support for 200MHz, but from what I hear, it still wasn't perfect.
I'd try either changing the ram, or turn the motherboard in for a KT800/NF2. Avoid the KT600, as it doesn't support dual channel ram.
http://www.via.com.tw/en/products/chipsets/# If you click on the "K7 Series" compare button, it also shows the KT400a as running single channel memory, which is in line with what I remember. The first dual channel controller I remeber Via using was the KT800. In short, you have a slow motherboard, try getting a newer one.

 

[TheSatori]

In short, you have a slow motherboard, try getting a newer one.

Ow, my heart

At least this teaches me to be even More paranoid when buying hardware. The chipset on my A7V400-MX SE motherboard is KM400a --- does what you say about the KT400(a) apply equally to that chip? (if yes, then we have the answer to the original question: the chipset.)

As for buying a new motherboard, I am pretty much out of options when it comes to a Socket A Micro ATX motherboard w. Dual Channel DDR400 memory support 😛 Suggestions, anyone? I found this one: ASRock K7S41. I know it's ASRock, but hey, at least it is not PCchip 😉 The ASRock K7S41 has the SiS741 chipset. Anyone tell me if it is all lies and fairytales, or does this motherboard actually support DDR400 memory? (I notice it mentions nothing about dual-channel. That does not bother me all that much (should it?)). From what I see, it does, but from prior experience, I best be absolutely sure.

Cheers,
TheSatori

 

[4745454b]

First, don't feel too bad about ASrock, its a rebadged Asus. No, the 741 doesn't support dual channel memory. For that you'd need the 756, 760, or 761. The problem is none of those chipsets support the Socket A. (athlon64 only...)
The 400a is supposed to handle RAM at DDR400 speeds. The problem is its picky about which ram to run at that speed. If you can't find a suitable replacement for the motherboard, try contacting Crucial to find out which sticks will work at DDR400 speeds in that motherboard. It SHOULD run it that fast, but again, Via had issues with that chipset.
In case your wondering, according to my PCModder library section, the following are Socket A chipsets that support dual channel memory. Nvidia: Nforce 2 ultra, Nforce 2 IGP. Via: KT880. No chipsets from ALI/ULI, SiS, or AMD supported dual channel DDR400 ram. I don't know of any mATX boards that had the NF2u, or KT880. These were performance chipsets, so probably didn't make it into smaller form factors.
I don't know how much performance hit your taking. If you had an Athlon64, I would argue the effect would be small, due to the integrated memory controller. My guess is dual channel would be ~10% faster, depending on test. Is there anyway for you to feel good about this? Only that you built it, and it works...