mem bus

[madcatmk3]

in calculating the loss would it actuly benefit mew to remove a stick? I would have 1.5GB but would run at 1T? Next PC I'm going Epox.

[yogurt_21]

No nForce based Mobo supports 1t with all DIMMS filled IIRC

what do you mean no? I've seen many people run all 4 dimms at 1T, whats the point of all four dims then? thats a performance loss not a gain.

shoot I ran my asus A7V880 with 4x256 (geil ddr 400 cl2.5-4-4-8)at 1T and you're saying an nvidia 939 chipset has an inferior memory contoller than a 462 via chip?

anyways it'd be better for testing with 1Gb on dual and see what you can do with that.

[hoinar]

I think he means double sided ram sticks.

[Aedan]

Originally Posted by yogurt_21

shoot I ran my asus A7V880 with 4x256 (geil ddr 400 cl2.5-4-4-8)at 1T and you're saying an nvidia 939 chipset has an inferior memory contoller than a 462 via chip?

The nVidia socket 939 based solutions shouldn't have a memory controller at all, as it's integrated on the CPU! There are issues running all memory banks (as opposed to DIMM banks) full at 1T - basically the memory controller on the CPU struggles to manage the timing.

The prime reason for this is that each bank of memory adds a bit extra load. When you have eight banks, the CPU doesn't have enough strength to drive all eight banks at 1T. Obviously this depends on just how much extra power each bank of memory requires to drive it. Memory that provides less of a load is more likely to run happily at higher speeds.

Also remember that as there's no latency between the memory controller and the CPU core, the memory controller can issue commands to the RAM faster than a system with a front side bus between the CPU and memory controller. Thus memory that works ok on an older FSB based system might struggle to keep up on a system where the memory controller is on the CPU.

[madcatmk3]

which isa what it makes it superior to netburst but still doesn't solve my problem.

[gedon]

as i ask this in your other thread, but have you installed the amd driver. this was the reason why my old system with a dfi nf3-u worked unstable.
maybe you have a bad memorycontroller or bios set at least one timing wrong

[madcatmk3]

AMD driver?

[madcatmk3]

I stilll don't know what the mem buss that ntune shows is!!!!

[yogurt_21]

odd I'll have to remeber that on 939 setups as it is I've always run 2 dimms on all my 939 setups still seems rather odd, makes 2x1Gb look alot better.

[gedon]

jepp, install the newest driver for your cpu.

[Aedan]

Originally Posted by madcatmk3

I stilll don't know what the mem buss that ntune shows is!!!!

It's the memory bus - the connection between the processor and the RAM. From memory, the clock speed for the memory bus is derived from the core frequency of the CPU. Basically, the core clock (speed) of the CPU is divided down to generate the clock signal for the RAM. This is the mem bus that nTune is showing you.

Things that affect this are anything that affects the speed of the CPU, together with the memory bus divider.

[madcatmk3]

why does it have such a low limit

[Aedan]

It doesn't actually. HT uses 8 data lines to transfer data IIRC, whereas the RAM uses 64 or 128 data lines to transfer data. That means the memory bus can run 8times slower but still transfer the same amount of information as HT.

[madcatmk3]

ahh thanks it still and irritating OC limit though.

[Aedan]

It's generated from the base clock frequency fed to the CPU, multiplied by the CPU's multiplier and then divided by the memory dividers. However, the dividers can only be set up at boot time, not when the machine is running, so you can't use nTune to alter them. You have to use the BIOS. (At least, this is from memory - can anyone confirm/deny this?)

[madcatmk3]

while you can bring up the speed the limit is still there.

[Aedan]

Yes, all clocks have a limit. However, with the dividers/base clock set correctly you should find that your RAM can't keep up well before you hit the limit. People have RAM running much faster than in your setup, as their dividers and clocks are set differently.

[madcatmk3]

for some reason my board deosn't like running DDR 400 still though so I can't up the speen even to the normal speed.