Need a 939 D/Core board which does 4 DIMMS?

[AbRASiON]

Hi guys,

I'm picking up my first Athlon X2 in the next week or two and sadly I have 4 dimms only at my disposal.

They are fortunately not cheap crap (all 4 are corsair XMS) and I don't really intend to run the ram out of spec.


Anyhow - long story short a pal recommended I get myself the Asus A8N-SLI Premium, price looks ok but I saw a post somewhere claiming it has problems with 4 DIMMS?

Anyone know if this is the case and if so, should I get another brand?
I was hoping to pick it all up at the same store (cheap one in Caulfield - don't think we're allowed to mention names?) - but I notice this particular store don't stock the DFI Lanparty which my pal also said is a good board.... suggestions / feedback?



Also, I'm hoping to use the "Scythe Samurai" CPU cooler on the board.
http://www.pccasegear.com.au/prod1888.htm

I don't know if I have revision 1 or 2 (picked it up about 12 months back - I still have the "AMD" bracket that came with it - but it's on my P4)

So I need a board which will fit that cooler preferbly.

One final thing - any reasons why I'd have problems with a 20 -> 24 pin ATX adapter? - don't wanna replace the 350W Antec.

Will be running a 3800+ btw.
(thanks)

 

[Diasper]

Perhaps not quite absolutely related - if you want to run your 4 dimms at 1T and without problem there's only one board capable of it - the new DFI crossfire board. Unfortunately, it can only do it to like 405mhz or so before having to revert to 2T.

 

[Peter]

As per PC3200 spec, running two DIMMs per channel at 200 MHz is past the calculated load for that speed. YMMV, but in general, that means you'll have to relax timings and/or lower the operating frequency. This is not a "problem", but the physical reality of signal integrity vs. parasitic capacitance.

Your board's BIOS will do exactly that, and may or may not let you tweak it back up to exploit whatever headroom your individual setup has over what the spec dictates.

Anyway, the impact of RAM speed onto actual system performance is largely overhyped.

 

[AbRASiON]

Originally posted by: Diasper
Perhaps not quite absolutely related - if you want to run your 4 dimms at 1T and without problem there's only one board capable of it - the new DFI crossfire board. Unfortunately, it can only do it to like 405mhz or so before having to revert to 2T.

I couldn't care less about 1T or 2T - as long as the ram isn't running pig slow

I just want to be able to use all 4 DIMMS - no serious overclocking here - maybe 2.0 -> 2.4ghz but ram to remain @ 400mhz.

 

[Peter]

Don't worry, 4 DIMMs (two per channel) is a setup that can be run at DDR333 speed (166 MHz) for sure, maybe even at 200, particularly if you use a recent revision E4 or E6 processor. They have been tweaked to have better chance of achieving this. But even if yours will run at (specified) DDR333 speed, that'll be enough throughput to not hamper general performance.

 

[AbRASiON]

but I don't want 333 - I want 400 speeds, it's 400 ram, with a CPU and board rated for 400.
Like I said, I don't care too much about 2T / 1T but I at least want the full 400mhz I've paid for.

 

[rise]

post 46

 

[AbRASiON]

So Rise: what you're basically saying is screw the A8N SLI Premium and go for the DFI?

That's running CAS 3 I notice but still 200mhz - looks good.

 

[Peter]

Originally posted by: AbRASiON
but I don't want 333 - I want 400 speeds, it's 400 ram, with a CPU and board rated for 400.
Like I said, I don't care too much about 2T / 1T but I at least want the full 400mhz I've paid for.

Face the facts. PC3200 (the DIMM standard for DDR400 RAM) is officially sanctioned for one single DIMM per channel. Anything past that is YMMV territory.

 

[AbRASiON]

Originally posted by: Peter

Originally posted by: AbRASiON
but I don't want 333 - I want 400 speeds, it's 400 ram, with a CPU and board rated for 400.
Like I said, I don't care too much about 2T / 1T but I at least want the full 400mhz I've paid for.

Face the facts. PC3200 (the DIMM standard for DDR400 RAM) is officially sanctioned for one single DIMM per channel. Anything past that is YMMV territory.

I wasn't aware of that at all - that seems kind of ridiculous to me.
I guess I'll just buy a board, try it at 2T and 400mhz - if it doesn't work I'll sell the ram and buy some new stuff.
I really think they should only include 2 memory slots if they can't do it properly with 4 - ridiculous.

 

[Steve]

It's about electrical load.

 

[AbRASiON]

Electrical load or not - I'm having problems finding info

Some places / people claim it'll work fine with relaxed timings, others claim that it'll be a crashtastic nightmare.


The place I'm buying from isn't too good on the return policy either

 

[rise]

sorry i can't be more help, i just remember seeing it done so i figured i'd link you at least one example.

whether its an eleectrical issue is beyond my limited knowledge but until recently there were people were saying 4 dimms= 2T as a cpu limitation which it obviously isn't.

 

[Steve]

It's not exactly a CPU limitation. The CPU's role is that in AMD64 architecture it contains the memory controller, rather than that being located in the chipset.

You *may* be able to get all DIMMs working at DDR400 speed, but (except where noted above) likely at 2T and perhaps raised voltage, which is out of JEDEC spec. JEDEC doesn't just throw out random numbers - one DDR400 DIMM per channel is what is calculated with consideration to electrical imposition (such as parasitic capaitance).

This is no fault of any chip maker or board maker, this is by design.

 

[evilharp]

DFI LANParty UT RDX200

DFI launches the first ATI Crossfire Retail board. With features like support for 4DS DIMMs at 1T and vDIMM to 4+V, it?s targeted at the AMD Enthusiast.

http://www.anandtech.com/mb/showdoc.aspx?i=2572

In the article, an FX-57 when used with this board can use 4 dimms @ 1T @ DDR400

 

[Steve]

That looks cool

 

[AbRASiON]

I'll just buy the A8N-SLI Premium and run it at 2T if it doesn't work I'll return it as faulty (as far as I'm concerned if it doesn't do 400mhz @ 2T that is faulty)

 

[Steve]

I was about to chew you out when I realized you said 2T and not 1T. Pretty sad when you need another shot of caffeine to think straight just before 10PM huh?

 

[2kfire]

400MHz @ 2T is probably slower than 333MHz @ 1T, depending on other timings.
Link <- Read the part about command rate (Scroll down until you find it or go to Edit->Find->command rate).
Link2 <- All the highest memory speeds are reached @ 2T, but the best performance is always @ 1T, at lower MHz.
Best bet would be to trade in your 4 sticks for 2 sticks (i.e. 4x256 for 2x512). Then you can have your cake (1T) and eat it too (400MHz)!

 

[rise]

1t vs 2t really means very little aside from synthetic benches such as sandra.

 

[2kfire]

The 2nd link shows a difference in Quake3 and Wolfenstein: Enemy Territory frames/second. Notice how at 400 Mhz 1T, FPS are the same as at 594 MHz 2T. But, at 'only' 556 MHz 1T (same timings as 594@2T), frames are 5% higher. When comparing 1T vs. 2T directly (same timings, same voltage) 1T @ 556 MHz is 5% faster than 2T @ 594 MHz. Not a big difference at all, but why choose higher MHz if it's slower?

 

[Reiniku]

I think you'll be wanting to look at the DFI LP CF or NF4 Expert which can run 4 tccd dimms at 1t.

The CF-DR is readily available for around 200 and the NF4 Expert will be within the week for around ~210.

 

[rise]

Originally posted by: 2kfire
The 2nd link shows a difference in Quake3 and Wolfenstein: Enemy Territory frames/second. Notice how at 400 Mhz 1T, FPS are the same as at 594 MHz 2T. But, at 'only' 556 MHz 1T (same timings as 594@2T), frames are 5% higher. When comparing 1T vs. 2T directly (same timings, same voltage) 1T @ 556 MHz is 5% faster than 2T @ 594 MHz. Not a big difference at all, but why choose higher MHz if it's slower?

look again. one is at 2380 and the other 2500.

 

[2kfire]

True enough... Link <- And this one is 4x512 compared to 2x512. In theory, same speeds/timings, so 4x512 should be better right, cuz it's 2 gigs compared to 1 gig?

 

[AbRASiON]

Well let's see - I'll pick it up this weekend, I can't live without 2gb of ram damnit - surprisingly HL2 was chugging on me! so sadly I guess it's time.

As long as the darn Nforce 4 is stable with the X2 (I mean rock fricken solid - like my P4 with i875p) then I'll be happy

Anyone know about my other 2 questions? Scythe Samurai cooler on that board or the 20 -> 24 pin adapter? - any problems?