Memory isn't running at specified rate.

[Slobby]

Hi all. New to the forums here. Hope I'm posting this in the right forum. I just recently received some memory. The product was Kingston HyperX T1 Series 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 1066 (PC2 8500) Dual Channel Kit Desktop Memory Model KHX8500D2T1K2/4G.

But its only running at PC2-6400... Which is 800 MHz right? Do I need to manually configure the memory to run faster? I was hoping since it was advertised at this rate it would work at it when I dropped it in. Is it a problem with the CAS Latency? I have absolutely no idea about how to set that up. I'm comfortable opening up my box and throwing new components in but as far as tooling around in BIOS I haven't done that.

My system specs if they help:
Mobo: AliveXFire-eSATA2
GPU: Radeon HD 5770
CPU: 64 X2 4800+ (Definitely next on my list to upgrade. Possibly in a month or two. Any suggestions are welcome. I think my mobo supports AM3)

[scaryjim]

Your processor doesn't support 1066MHz memory. Remember that with AMD processors the memory controller is on the CPU not the motherboard. 1066MHz memory support didn't come in until AMD launched the Phenom series of processors.

Also, while your motherboard technically supports AM3 processors, it's limited to the old (HT1) HyperTransport connect, rather than the HT3 used on Phenom, Phenom II and Athlon II processors. That said, the CPU support list appears to cover every AM2/2+/3 processor aside from the Phenom II X6s, so there's no reason you can't upgrade it, but personally I wouldn't go any higher than an Athlon II X3 on that motherboard. The slower HT will be a factor in some tasks.

[Slobby]

Ah okay thanks so much for the help. Once again let me point out that my technical know how is not particularly high.

Athlon II X3 is AM3 right? So I would be safe going with any AM2+ processor? This is the one I'm looking at: AMD Phenom II X4 940 Black Edition Deneb 3.0GHz 4 x 512KB L2 Cache 6MB L3 Cache Socket AM2+ 125W Quad-Core Processor HDZ940XCJ4DGI - OEM

It is less expensive than:AMD Phenom II X4 920 2.8GHz 4 x 512KB L2 Cache 6MB L3 Cache Socket AM2+ 125W Quad-Core Processor HDX920XCGIBOX

Was also looking at:AMD Phenom II X3 715 Black Edition Heka 2.8GHz Socket AM2+ 95W Triple-Core Desktop Processor HDZ715WCJ3DGI - OEM

These would speed up my systems considerably and unlock the 1066 ram correct? Any suggestions on which one I should purchase?

[scaryjim]

The PII 940 is a good processor, and is AM2+ anyway, but as I said you won't get the full benefits on that motherboard because it only supports HT1. HyperTransport is the speed of the link between the CPU and the rest of the computer, and could potentially be a bottleneck if you go for too high end a system (which is why I recommended saving money and going for an Athlon II). AM2+ and AM3 use a HT3 link which is more than twice as fast as HT1. I've not personally seen any direct comparisons of performance with the same processor at HT1 and HT3 speeds, so I don't know how big an issue it might be. A HT1 motherboard will provide ~ 6.4 - 8GB/s theoretical peak bandwidth for all communication between the CPU (and therefore the memory) and the rest of the computer. A single PCIe x16 (v2) slot provides the same theoretical bandwidth, but it's been fairly well documented that actually dropping to a v2 x8 link (i.e. half the bandwidth) has only a very small impact on framerates. So your graphics card alone probably won't swamp an HT1 link, but it won't leave a huge amount of bandwidth for all the other communication that your computer needs.

hmmm, lots of waffle there, sorry

I think on the whole the HT bottleneck won't be severe enough to make a significant difference to your experience, so really the question is this: do you want to be able to upgrade the PC again in the future to AM3 / DDR3, or will you do a complete rebuild next time you upgrade? If it's the former then obviously get an AM3 processor (e.g. a Phenom II X4 955BE) so you can do a motherboard and RAM upgrade in the future to get the benefits of HT3 and DDR3. Otherwise, I'd personally go for the Phenom II X4 940 as long as it's no more than £110. Any more than that and you might as well get the 955 anyway, since it's got a higher stock clock speed and an unlocked multiplier...