Can 4GB (2 sticks of 2GB) DDR2 be run at 1T Command Rate?

[GundamF91]

I have 2 sticks of 2GB A-Data DDR2-800/PC2-6400 modules. No matter how many times I set it as 1T command rate in Abit IP35E's BIOS, the CPUz always show them running at 2T.

Has anyone gotten 4GB ram to run at 1T Command Rate? This is under Windows XP, so it's only 3.25GB, but that shouldnt' really matter.

 

[JustaGeek]

I do not think that Intel chipsets will even let you run it at 1T.

BTW, the performance difference on an Intel platform is negligible, regardless of the chipset...

And it is next to impossible to be 100% stable...

Just stick to 2T.

 

[MegaWorks]

I tried to set the 1T Command in the bios but CPU-Z still shows 2T. I think JustaGeek is right intel chipset won't let you set 1T.

 

[secretanchitman]

i dont think any chipset will let you run 2T with 4GB....but yes, justageek is right that the intel chipsets wont see any performance decrease....on the other side of the world (aka, amd chipsets), they take a noticeable hit. i ran 2x1GB + 2x512MB and man....felt slower, although i had a total of 3GB to work with. this was in xp pro sp2 32 bit btw.

 

[BonzaiDuck]

We've discovered some other things about the Intel chipsets -- per what you can "tweak." There may be latency settings, for instance, on my 680i board that just aren't implemented in the Intel chipset models.

Prevailing experience suggests that a 1T command-rate is possible if only two modules are used. This may not apply so easily to 2GB modules, and apparently doesn't apply for certain boards using one or more Intel chipsets.

I want to determine this on my own, which is why I want to find some stellar 2x2GB kits (like the G.SKILL DDR2-800 or -1000's.)

EVen with a 2x1GB kit, a 1T command-rate will be achievable for a particular set of latencies at less than the upper FSB limit for those latencies. It may require some additional voltage over the same FSB and latency settings and a 2T command rate.

I've found that I get the best bandwidth with a slightly lower over-clock and the tightest latencies together with 1T. But I limit my options to voltages below the recommended maximum -- 2.2V in my current configuration.

 

[brencat]

Originally posted by: BonzaiDuck
I've found that I get the best bandwidth with a slightly lower over-clock and the tightest latencies together with 1T. But I limit my options to voltages below the recommended maximum -- 2.2V in my current configuration.

And for the record, Bonzai runs a 680i mobo...hence 1T cabability.

@ Gundam, IIRC you are running that chip @ 300 x 10, correct?

Use the 1:1.25 divider (RAM @ 375) and try to get your timings as tight as possible. Not sure if you'll be able to run CAS3 or not (I couldn't but I also have 4 slots filled), but you'll certainly be able to run 4-4-4-8 and probably 4-3-4-9. I was able to run 3-3-3-6 at 1:1 (FSB:RAM @ 325) with all 4 slots filled, but the system was slower and benched worse for me than my current setting.

I'm also curious if your 2gig sticks will run these same two timings with the 1:1.5 divider (RAM @ 450) and what voltage is required. Anyway, if you get around to it, let us know!

 

[cmdrdredd]

with 2GB I can run 1T but 4GB (4x 1GB) I can't. The benchmarks are the same either way.