Async vs Sync.

Hello.

Is it correct that the HT bus and RAM bus must be in sync, when overclocking the Athlon 64 X2?

My system:
Athlon X2 3800+ (2Ghz@2.6 Ghz)
Twinx1024-3200XLPT (200 2-2-2-5 1t @ 260 3-4-4-8 2t)
Asus A8n-e bios 1010.
Powercolor x850xt.
Western digital 200 Gb HD.

I have overclocked my CPU to 2600 Mhz, by raising the FSB to 260 and not touching the RAM ration (1:1). Id had to change the timings to 3-4-4-8 2t. Which is pretty awfull! I can't figure out if I should go for a high RAM bus. (520) Or use a RAM divider - async HT/RAM bus, with better timings. I hope someone can clear this out for me!

Best regards.
Asbjørn Morell.

No, it doesn't matter at all.

The A64 chips don't suffer from async RAM/FSB operation like the old XP chips. I run my A64 at 250MHz FSB with a 333MHz RAM divider, giving my RAM an overall speed of 208MHz. This allowed me to keep the timings fairly tight, and my system still pounds through games like there's no tomorrow.

Point being that on AMD64 architecture, there is no front side bus to be "in sync" with - the RAM controller is inside the CPU and runs at full CPU core (!) frequency. RAM bus speed divides down from there, e.g. RAM=CPU/12 if you got DDR400 on a 2.4 GHz CPU.

I have 1 stick 512ddr333 and 1 stick512ddr400 and my system runs
fine. Will it matter when I get my new A64 if I mix my memory like I'm
doing now?

The same thing will happen as elsewhere - timings and frequency will be chosen to suit the slowest of the detected DIMMs.

To run these two in dual-channel mode, they'd have to have identical geometry, e.g. double-sided 16-chip.

Quote: Originally Posted by Peter M
The same thing will happen as elsewhere - timings and frequency will be chosen to suit the slowest of the detected DIMMs.

To run these two in dual-channel mode, they'd have to have identical geometry, e.g. double-sided 16-chip.

The A64 I ordered has only single channel memory controller. So
that being the case, will the one ddr333 chip lower my cpu frequency?
I ordered a 3000+ 2.0ghz 1.6ghzbus.

Ah. Two DIMMs on the same channel, by how the DDR DIMM standard is defined and calculated, demands 166.67 MHz (DDR333) operation anyway.

The 2000 MHz CPU will run this RAM setup on CPU/12 for exactly 166.67 MHz. Hence, everything's to the best of abilities your DIMMs bring.