I assume you're talking about an AMD64 system - if not, let me know, because the following won't apply.
Because AMD64 systems have the memory controller integrated into the CPU, the limitation that dual channel systems only support 1T command rate timings with 2 sticks of RAM, and revert to 2T when 4 sticks are used, is not specific to any particular motherboard, and there's no way for a motherboard to work around it.
Your best hope is that you'll find four single sided 512 MB sticks or two double sided 1GB sticks that support 1T command rate timing, in an AMD64 system. I'm not aware of these, and you may want to keep an eye on Anandtech (or similar) for news on new DDR RAM chips being developed.
Given that you can still maintain 2-2-2-10 2T timings with 2GB, if your applications will utilise that much memory, then you'll still find 2 GB at 2T faster than 1 GB at 1T.
Edit: memory controller integrated...
X2 4200+, XP-90 + Nexus 92mm, VTX 5750, SLK3700-BQE + AcoustiPack, 2 Nexus 120mm, Asrock 939Dual-SATA2, Raptor 74GB, Pioneer DVR-109B, S12 430. [url="http://www.silentpcreview.com/forums/viewtopic.php?t=16171"]SPCR thread[/url].
[url="http://www.silentpcreview.com/forums/viewtopic.php?t=48281"]HTPC build[/url] - NSK2480, Biostar TA690G, 4850e, Asus EAH5570 Silent, Minja, 4 GB RAM, WD GP .75TB + 1.5TB, iHES208 BD, Win7MC.
Last edited by Spod on Thu Dec 02, 2004 8:42 am, edited 1 time in total.