Can't get Asrock Mem Speed above 153Mhz

[Frank_Rizzo]

Asrock 939NF4G-SATA2 with 2 x 512Mb Corsair Twinx 2-3-3-6 ram and 3800+ X2 @240Mhz

What ever I do the ram bus speed is always 2x 153Mhz (306Mhz data rate)

Have set ram speed to auto, 166,200. Have set CPU bus speed to auto, sync, async but it always forces the ram bus speed to 153 according to Sandra.

This is the mobo with onbard vga sharing the ram. I know that there is a performance hit with this but surely it should be running at 200Mhz?

 

[Minstadave]

Asrock 939NF4G-SATA2 with 2 x 512Mb Corsair Twinx 2-3-3-6 ram and 3800+ X2 @240Mhz

What ever I do the ram bus speed is always 2x 153Mhz (306Mhz data rate)

Have set ram speed to auto, 166,200. Have set CPU bus speed to auto, sync, async but it always forces the ram bus speed to 153 according to Sandra.

This is the mobo with onbard vga sharing the ram. I know that there is a performance hit with this but surely it should be running at 200Mhz?

Try using CPU-Z to confirm the memory speed

 

[Frank_Rizzo]

Still the same with CPU-Z

Type: DDR
Channels: Dual
Size 1024 MBytes
Frequency: 153.3 Mhz
FSB/DRAM CPU/15
Cas# 2.0
Ras to Cas: 3
Ras precharge: 3
Cycle Time (Tras): 15
Bank Cycle Time (Trc): 22
DRAM Idle Timer 256
Command Rate 2T

CMX512-3200C2

What I don't understand also is that CPU-Z timings table shows:

Freq 200Mhz
Cas# Latency 3.0
Ras to Cas 3
Ras Precharge 3
TRas 8

So this is rated as 3-3-3-8 @ 200Mhz and yet the spec of this ram is 2-3-3-6

 

[Frank_Rizzo]

I reverted the CPU speed to normal and now get proper memory speed so it looks as if the mobo was putting in too high a divider.

O/C'ing back to 230 FSB and lowering all the mem settings put in a /10 divider = 230 mem bus speed.

Too bad this mobo is not so flexible on the memory speed option. I guess it's just a matter of trial and error finding the optimum values.