Ram Dividers -- wtf is going on

Okay here's the scoop.. I am building a P4 system (ugh!) for a guy at work, and I cannot get 1024mb to run 1:1 for the life of me. It wants to run the RAM at 160mhz for some reason.

The motherboard is a Socket 775 Asrock model that is based on the 865GV chipset. It has the option to manually set RAM frequency in the BIOS, but even after switch it to 200mhz (400 DDR), Sandra and CPUZ report it running at 160mhz.

The peculiar thing is that if I remove one DIMM (leaving a single 512mb stick), it will run DDR400 just fine.

WTF is going on here. I downloaded the latest BIOS and installed it. I need to get this RAM running top speed.

RAM is Buffalo B-line PC3200 rated at 2.5-4-4-7 (as the BIOS detects it). The chips on the modules say M+S. It's being sold at 73$ on Newegg for a 512mb module.

maybe the ram isnt compatible? Did you set divider on 1 to 1? Did you place one stick in the matching slot of the other, as in, green with green, and so on?

Everything is setup and configured properly.

There are only two DIMM slots, dual channel is activated with the use of two DIMMs.

There is no divider option in the BIOS per se, but it allows you to set the memory frequency, which I have set to 200mhz. Since I'm running the FSB at 200, this should equate to a 1:1 ratio.

I'll have to try some other RAM I have lying around, but this stuff should cut the mustard. Stupid Intel, now I know why I've been using AMD for so long... I just used this same RAM on an Asrock KT880 board and it worked fine in DC @ 200.

what are the options for memory speeds on your board? Usualy they are 400,320,260 400 = 1:1 320=5:4 260=3:2 on asus boards. Did you try both chips individualy to see if they both are good?

it happens, running 2 modules is not guaranteed. I had 2 infineon that gave me that problem on an A64 board. 2 modules = ddr333 operation. Either 1 alone = 400. Sold them and got 2 samsung which do DDR400 with both modules in.

Well that bites..

I was aware of this problem in single channel Athlon 64 motherboards (high speeds w/ 4 banks populated), but I assumed 2 x 512mb to be okay on a dual channel I865 chipset.

The available options on bios are: DDR400, DDR333 (which runs at DDR320 for a 800mhz FSB CPU), DDR266. Like I stated, even when manually setting to DDR400, it remains at a 5:4 ratio... Grr..

Oh well, the board is still allowing me to go past 160 mhz on the RAM by overclocking the FSB. Although I wasn't planning on overclocking this system, it looks like I'll have to in order to gain some of that precious RAM bandwidth back. This LGA775 2.8 seems to have plenty of headroom, it's been priming at 3.2ghz for several hours now on stock cooling and voltage. I just hope this crappy 430W generic PSU is up to the task...

jaydog said:

what are the options for memory speeds on your board? Usualy they are 400,320,260 400 = 1:1 320=5:4 260=3:2 on asus boards. Did you try both chips individualy to see if they both are good?

Click to expand...

Yes they both are good. In fact, I was able to tight the timings considerably at 160mhz, down from a 2.5-4-4-7 stock to 2-3-3-6 stable. Getting closer to the 200mhz mark (overclocking the FSB) I had to use 2.5-3-3-7.