Memory Timings & Voltage

[ShEsHy]

So, here's the deal; I'm not quite ready to get a completely new computer, so I picked up a set of cheap components second hand. I got an ASUS P5Q Deluxe, Intel C2D E8400 (now I have 2 of them ), Scythe Mugen and Mushkin 2x2GB DDR2 PC2-6400 4-4-4-12 Blackline 800MHz (996580) for 110€ .
From my old system I kept an MSI N9600GT-T2D512-OC and GEIL Gaming Series DDR2 800MHz 2x2GB PC2-6400 (GB24GB6400C4DC).

I inserted both RAM kits (Mushkin in Channel A and GEIL in Channel B), and set the Timings and RAM Voltage in BIOS to their specifications (both kits at 4-4-4-12 and 2.0V), but now I'm not sure if those settings were applied to both kits. I'm not really that good at understanding the SPD tab in CPU-Z, but on first glance it looks like the settings were only applied to the Mushkin kit:


So, am I reading it incorrectly or did I miss something in BIOS?

 

[jaquith]

First mixing different RAM and especially when the Voltage is different is never a good idea, worst the CAS Timings are also different.

At best you have to use the Worst of either set:
DDR2-800 4-4-4-12-2T @ 2.05v ; set 1
DDR2-800 5-5-5-15-XX @ 1.80v ; set 2
======================
DDR2-800 5-5-5-15-2T @ 2.0Xv ; this is what you need to Manually set in the BIOS then test extensively with Memtest (4+ passes)

The Memory tab (applied to all RAM per BIOS) shows the RAM is running according to the Frequency and Timings of set 1, 'SPD' tab shows the available Frequency/Timings/Voltages available (encoded) in each stick.

 

[ShEsHy]

But the thing is, the voltage and timings aren't different (before I bought the Mushkin kit I made sure that both kits ran on 4-4-4-12 @ 2.0V).
It says 4-4-4-12 @ 2.0V on the GEIL sticks themselves (2nd set) and on the box I got them in when I bought them (around 4 years ago). You can also see that they should work at those settings on GEIL's website under the specifications tab: http://www.geil.com.tw/products/showSpec/id/119

So, did I get a mislabeled set or are they able to run on 4-4-4-12 @ 2.0V, but the voltage I set in BIOS doesn't apply to the 2nd set for some reason?

Also, just to make sure, are both sets running on 800MHz (I just installed PCMark and it says they're running at 667)?

 

[jaquith]

Actually looking again, use DDR2-800 5-5-5-18-(Command Rate 2T optional) @ 1.80v - it'll be a better setting. If there's instability use Command Rate = 2T and if needed 1.90v.

Sets and revisions change, look at the 'SPD' tab for ALL of the sets. In the CPU-z Memory tab it says the DRAM Frequency = 400MHz * 2 = 800MHz (DDR = Double Data Rate), PCMark is wrong.

 

[ShEsHy]

Good to know at least the frequency works as it should.

From your comments and re-checking the SPD tab, I'm guessing that in a manner of speaking, I'm OC'ing the GEIL kit to run as is advertised (ie all sticks are running at the timings and voltages I set in BIOS, but those listed in the SPD tab are what they're able to run at if left at auto)?

 

[jaquith]

Memory Frequency's 'Default' aka Auto is a function of the CPU and in older PC's like yours the FSB/BCLK and CPU. Yeah, you are OC'ing the RAM CAS Timings beyond the Rated and encoded Frequency/Timings which is why I strongly recommend testing the RAM more toughly with Memtest. The lower (faster) CAS Timings help, but errors i.e. corruption and or BSOD's 'can' be the price.

 

[ShEsHy]

Will do. I'll probably leave it running overnight and then report the results tomorrow.
I'd lower the timings and voltage, but I at least want to get what I paid for, so I'll leave it as is for the moment (haven't noticed any problems yet).

 

[jaquith]

If it passes leave it, fails change it -- Good Luck!

 

[ShEsHy]

Left it running for 7 hours and 3 seconds . It made 4 passes and found 0 errors. I also just played a Supreme Commander: Forged Alliance game versus 3 Turtle Sorian AIs (extremely CPU intensive) and had no issues.
Therefore, I'll keep my RAM on 4-4-4-12 @ 2.0V.

Thanks for all your help.

 

[jaquith]

COOL!!!