What affects latency?

[Energize]

Say if you double the clock speed of the memory, but keep the timings the same, would that halve the latency?

And does running multiple smaller sticks of ram, increase or decrease latency like hdds in raid?

 

[Cob]

Doubling the clock speed and keeping the timings will double the bandwidth.

Two sticks in dual-channel mode will also (in theory) give you twice the bandwidth of a single stick in single-channel mode.

 

[Cyber-Mav]

Two sticks in dual-channel mode will also (in theory) give you twice the bandwidth of a single stick in single-channel mode.

thats true to a certain point. the interface between the cpu and ram needs to be quick enough to saturate that memory bandwidth for it to be truly available.

e.g the nforce 2 chipsets had dual channel memory support but max official bus speeds were limited to 400mhz which resulted in to slow a link between the cpu and ram to actually get double the memory bandwidth.

 

[WJA96]

Say if you double the clock speed of the memory, but keep the timings the same, would that halve the latency?

And does running multiple smaller sticks of ram, increase or decrease latency like hdds in raid?

Latency is a feature of electrical charge on silicon, so you cannot change it unfortunately. The differences between sticks lie in how the chip is made (physical size etc.), what it is made from and how much voltage you apply to it. It's physics, so you can't mod it.

You can buy low latency large capacity and high latency low capacity - it depends on the depths of your pockets. Intel memory controllers don't really do that much better with low latency RAM - better to increase capacity and bandwidth.

 

[Corasik]

Say if you double the clock speed of the memory, but keep the timings the same, would that halve the latency?

And does running multiple smaller sticks of ram, increase or decrease latency like hdds in raid?

More sticks generally makes the latency worse, as the memory controller has more work to do keeping the sticks in sync.

If you are able to keep the same tight timings at two difference clock speeds, then yes, the higher the clock then the lower the latency, crudely put, cas 3 memory uses 3 clock cycles of latency for access, so if your memory runs at 266, and 533 with the same cas, then 533 will be lower latency.

Unfortunatly its often the case that clocking higher requires slacker timings for the very reason WJA96 mentions. Its a lot easier to make high bandwidth memory than low latency memory.

Intel chips do still benifit from low latency memory, infact I've always found that memory at 1:1, and the tightest possible timings generally gives best performance on intel platforms, as anything faster just hits the FSB bandwidth wall. Of course if your able to overclock to insane levels, then of course you need very high bandwidth ram to keep that 1:1 ratio.