Fireblade2K4 said:
What do the HtperTransport Multipliers on this board do, there are settings Auto, 200Mhz, 400Mhz, 600Mhz, 800Mhz and 1000Mhz.....how do these impact system performance, stability and what other settings effect/impact these?
I've been messing with the HTT and DDR clocks most of the day knowing pretty much what I'm doing but im lost with these other settings, there appear to be 2 places in the bios where they show up, some for the Northbridge and some for the Southbridge, I am new to A64 systems, little different from the old XP's when it come to overclocking, lol.
Any pointers greatly appreciated.
Stu
I had the same trouble. I've been pootling along with a straightforward FSB x multi = CPU clock for years and K8 is a bit different. It doesn't help that the BIOS settings on this board are incorrectly labelled.
The two settings you mention are for the HyperTransport links between (i) the CPU and the northbridge and (ii) the northbridge and the southbridge. I can't think of a reason why you'd want them to be set differently to each other, but the option is there.
The settings for them are not as they are stated to be. They are not 200MHz, 400MHz, etc. That is simply wrong. You're right in thinking that they are actually multipliers, set relative to the base speed, the HTT, the "sort of equivalent to the FSB setting on other architectures speed", or whatever name you prefer for it.
. '200MHz' is 1x, '400MHz' is 2x, etc. 'Auto' is unspecified, so who knows what it does? My guess is that it selects whatever multiplier would give a hypertransport speed closest to but not greater than 1GHz (e.g. if you set the base speed to 245MHz, Auto would set the HT multi to 4x).
In terms of stability, don't go over 1GHz. They're really intolerant to running over-spec. You can get major instability just a couple of percent over-spec.
In terms of performance, you're probably fine running them well under spec. There's oodles of spare bandwidth on them at stock speed and width (i.e. 1GHz, 16-bit), so you can certainly cut the bandwidth by a third without any performance loss. Maybe more.
I'd keep them at 16 bits wide and alter the multi manually to get the closest to 1GHz without going over at all. That should never give you less than 753MHz (251x3), which shouldn't reduce performance at all.
