Newbie to DDR, what timings to try other than fastest?

I just got a P4S533 board up and running last night, with a 1.6a known to do 160 FSB at 1.8 vcore on another board. I currently have it at 150. I have genuine Samsung PC2700 and want to see whether I can hit 200 mhz or DDR400 using the mem dividers.

Well at 4:5 (board doesn't have 3:4) or 187 mhz, I can't do 2-2-2-4-1, which I presume is the fastest timing. So what combo do I try next to see if I can run stable at 187? I know the ram will do 176 at fastest so looks like my limit is around 180, what other people have noted also. Ram is not burnt in but I'm not going to bother.

The settings in the BIOS are:

SDRAM CAS latency: 2T/3T
SDRAM RAS to CAS delay: 2T/3T
SDRAM RAS precharge time: 2T/3T
SDRAM RAS action time: 4T/5T (think there are other settings like 3 and 6 also, I forget)
SDRAM command leadoff time: 1T/2T

At 150 1:1 I got a Sandra memory score of around 2200/2100. If I set the ram to SPD in the BIOS and run 4:5, a whole bunch of 4 settings are set and I get a pretty decent memory score of around 2550/2500. I know if I could do fastest timing at 187 mhz I should see around 3k/3k.

I use cas 2.5- tras 2-trcd 2- action time 6 - leadoff time 1T at 204mhz.

The cas 2.5 or 2 made only a 10 point differnce in sandra at 180 for me. The trcd made a 50 point difference between 2 or 3.

You might be able to keep your action time at 4 or 5 since you are at 187.

187=about ddr 3100 so if your chipset were 100% effecient you could score 3100 in sandra mem bench but the sis 645 is only about 88% effecient meaning at 200mhz(ddr3200) you score about 2900 the 645dx might be a little better.

personally i got for turbo settings, with a bit slower FSB. Yes i can run at 205 with normal or fast timimings, but it is just a bit unstable and needs more memory vltage than i like to give it so i just leave it at

9.5x185

cas 2 turbo 2-6-2 with 4 ay interleave, and 1t cmd rate....geta about 2600 in sisandra. but that is just me

Sorry if I'm a little off topic..

but hey jason, what revision of the Epox mobo do you have? I'm about to build a setup that's almost exactly like yours except for the processor..wondering if you have had any problems with the board...