mystified by DDR400 support on KT400 chipset board

[imashination]

The FSB is not the RAM speed, your CPU can safely run at 333 (166) while the ram runs at 400 (200)

[singularity2006]

ooh wow. How weird. I was trying to figure out how to get that thing in there. Anyhow, with my current settings, my FSB is 166, divider as 5, and DRAM only @ 166. For some reason, those settings won't let me have a 200MHz clock for the RAM. If left to detect by SPD, it only gives me 166.

However, it will enable the 200MHz clock when I set the divider to 3. But then everything gets really funny...... any ideas? I was trying to get everything so I could get an even 66MHz AGP clock and 33PCI clock but none of the multiplier combinations and divider combinations are yielding that with a 200MHz RAM clock..... really weird. Suggestons?

[singularity2006]

ah scratch that. After reading through Soyo's knowledge base, it turns out that I will get DDR400 speeds only if my CPU is also a 400MHz FSB CPU (this is specific to the KT400 only). The one I have is only a 333 so I'm stuck until I upgrade that. But in that case, since I'm underclocked, what other things could I do with timing to perhaps achieve some performance gains? I'm still running @ only about 84% efficiency w/ a bandwidth of about 2275 (that's w/ upping the voltage to 1.7. Normally I get 2200). I was reading from Corsair's Ram Guy Form that the voltage should be upped to 1.7V. But isn't modifying the voltage like that kinda risky? I did it last night for a little while and it gave me that slight 2% boost in bandwidth but then I read somewhere about heat issues so I set it back to defaults. But if modifying voltages isn't too risky, what should they be changed to?

And since we're on the topic of upgrades too, anyone happen to know when the Barton 3000+ will drop in price? Getting a new Barton 3000 @ a 400MHz BUS would be damn sweeeeeeeet..... :drool: (I don't have any apps that currently take advantage of Athlon 64 so it would be a waste of $$ at the moment).

[CgFX]

333 FSB with 333 DDR is typically faster than 333 FSB with 400 DDR (due to sync vs. async issues).

This is especially true on the nForce2 mobos and I assume it is likely true with VIA as well.

[imashination]

Originally posted by singularity2006
I'm still running @ only about 84% efficiency w/ a bandwidth of about 2275 (that's w/ upping the voltage to 1.7. Normally I get 2200).

You DO realise that the Athlon speed rating (eg 2500+, 3000+) isn't the actual MHz speed it runs at right? Please tell me you know this. Please tell me you're not trying to make an Athlon 2500+ run at 2500 MHz.

Please, it will give me much more faith in the human race.

[singularity2006]

yeah, I know that's not the actual speed. When I say 2275 and 2200, I'm referring to my RAM's MB/sec that I get from running the SiSoft Sandra memory bandwidth meter.

[imashination]

So what makes you think youre only running at 80% performance?

[singularity2006]

I'm just comparing my current RAM bandwidth with the theoretical max. SiSoft Sandra reports that I'm getting about 2200MB/s so I'm just taking that and dividing by 2700MB/s, which yields about 82%.

And on another note, Anandtech reports that trying to use DDR400 on their Soyo system lead to a performance drop. But then again, I think their test was when the board first came out. Do you think this performance issue would be corrected with the later BIOS revisions?

[3Dfx_Sage]

80% efficiency??? that's GREAT! You should be HAPPY with that! If you want to get more, adjust ram timings.

[singularity2006]

really? I was under the impression that people usually got more than that... hahahaa. There was this one thread in particular that everyone was getting like 90% and adjusted timing provided near 100%!

[3Dfx_Sage]

Originally posted by singularity2006 There was this one thread in particular that everyone was getting like 90% and adjusted timing provided near 100%! [/B]
WAHAHAHAHAHAHHAHAHAHHA thats TOTAL BS. Those people were just trying to brag, its not possible.

[singularity2006]

ooocha. OK.

Okay, here's the next question. I was reading on the Corsair RAM Guy form that it is possible to run the VS512MB400 in dual channel mode. My question is, what is dual channel mode and how do I enable it with my Soyo Dragon KT400 Ultra Platinum board?

On Soyo's site, it said something about how this board only supports 2 sticks of RAM at any given time that is faster than PC2100 (if all the RAM is PC2100, all three slots may be used). However, this means I can only use RAM slots 1 and 3. I'm using 2 and 3 right now and it works fine. What is their reasoning behind that?

[imashination]

Dual channel = RAID0 for RAM, this is always limited to 2 specific slots.

[singularity2006]

ah, so am I correct to assume that Soyo's reasoning for using slots 1 and 3 is for the dual channel nature of the RAM? If that's the case, how would I verify if it is indeed functioning in dual channel mode? I actually just switched the RAM positions around so only 1 and 3 are used but the SiSoft Sandra benchmark didn't yield any performance gain.... or should I not expect any performance gain?

[3Dfx_Sage]

KT400 does not support dual channel

dual channel is not limited to two slots, but rather it uses two sets of slots. they can be sets of just one slot, two slots, 4 slots, or even more slots. I think on the nForce2 even its a set of one and a set of two on the other.

[singularity2006]

Ah, okay. So why is it Soyo's site say that if I'm using anything faster than PC2100 that I can only use slots 1 and 3 whereas it's been working fine using 1,2, or 2,3?

[3Dfx_Sage]

Originally posted by singularity2006
Ah, okay. So why is it Soyo's site say that if I'm using anything faster than PC2100 that I can only use slots 1 and 3 whereas it's been working fine using 1,2, or 2,3? umm... because... they dont know their own products very well...? who knows

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