Problem with P5K and Corsair - need help

I just built my first computer and I'm using a ASUS P5K with Corsair XMS2 800Mhz DDR2, 5-5-5 timings ram. (4-1GB sticks) I tested each of the 4 sticks individually in the first slot and only 1 gave errors. (on Memtest86+) So I tried the 3 that passed and it gave errors. If I try any 2 stick combo, of the 3 good ones, it works fine. But as soon as I try to use 3 at once, it gives errors. A rep at ASUS said that ram model isn't on the Qualified Vendor List, but it looks to be Ok'd at Corsair's website. The Corsair Value Select 667Mhz is on noth websites to be ok, would I be better off just going with what the ASUS guy said and try to exchange the 4 sticks I have for the 667 VS? Or are there some other troubleshootings that I can try first? All I can change in the BIOS, is the Frquency, from Auto to 800 or 667, and I can change the timings from auto to 5-5-5-12. (another point, the ram says 5-5-5-12 on it, but their wensite says 5-5-5-15???)

Any ideas would be helpful, I think I may need to rma at least that 1 mem stick, but that doesn't explain not being able to use the other 3 together?

which dimm slots are you using? i think you might have a bad dimm slot as well.

I would hope that's not too much for the P5K to handle.

Just a thought, but would bumping the voltage on the bridge chips maybe help?

well if running stock speeds there is no need to up the mch volts. now that i think about it though have you made sure to set to the recommened vdimm for the ram? as well to rule out bad dim slots and ram stick with the suggest timings on the Manfacture site.

sorry, went out to lunch for awhile.....but did have a little break through finally.....on suggestion, I took the 3 sticks that passed memtest individually, put them in the first 3 slots, (A1,B1,A2) and manually changed the frequency from Auto to 667. (the ram is 800) It did 3 passes over 3 hours on memtest with no errors, this is the first time I've gotten more than 2 to work. Seems a bit odd solution wise, I know the 4th stick is bad, I will rma that one, but Vista 32 only sees maybe 3 GB anyway so not a big deal. It does seem odd that more than 2 GB at 800Mhz is too much for the P5K, however, when I called ASUS this morning, they did tell me that ram (5-5-5-12) is not on their Qualified Vendor List, the only Corsair at 800mhz is the same as mine but with the 4-4-4 timing. Odd.....How much of a difference would it be to leave it at 667 instead of 800, and mostly, is this a good viable solution, or am I jerry rigging this machine and will see problems in the future? Thanks!

oh yeah, I have yet to mess with the voltage settings in BIOS, scares me, I have the timings set to Auto right now as defaulted. Though I did try setting the manually before and didn't help, only going from 800mhz to 667mhz just now makes a difference so far.

oh yeah, also, I'm not sure what the vdimm is for the ram or how to adjust it.....and I did move the good sticks around to some different slots last night and didn't find any one in particular that always failed....and right now I have sticks in 3 of the 4 and it passed memtest......are there any other diagnostics I should run to make sure it's performing good at this setting?

vdimm is just a short name for ram voltage. The specs on their site do include the voltage needed. should be something like 1.9volts for the ddr2-800 5-5-5-15 sticks if i recall correctly.

The ram voltage will be under the same section as the cpu voltage option.

ok, I'm gonna go check it out in the BIOS, another weird thing about this ram, the timing printed on the back of each stick is 5-5-5-12 and the timing on the website is 5-5-5-15.......which one to go by??

I just checked and there's no where in my BIOS to change any voltage settings, you can only see the voltage displayed in the power monitor screen which is the real time view of cpu temps etc.... but no where can you adjust any voltage settings, for ram it's only frequency and timing, and nothing under the cpu config menu.

its in your bios
http://www.xbitlabs.com/articles/mainboards/display/asus-p5k_7.html#sect0
look at the third pic from the top of the page. under your (advance tab/jumper free) last set of options are for voltage.

Dont forget to update your BIOS to the latest once.

As well as, on memtest86, run test 5 only, that will save you 3 hours of testing.

question - about running test 5 only, I guess first off how, and secondly, I have seen my ram come up with errors on tests 4 or 7 as well though? Wouldn't that give misleading results? Thanks

ok - I just got home and I had run memtest (all tests) with all 4 GB in and the speed lowered from 800 to 667. (voltage and timings still at auto) it ran 5 passes in about 4 hours or so, and zero errors! So I'm not sure as to why this is the solution, but after the past couple days with this, I'm fine with 667. I just want the system to be stable more than anything, so I'll watch it over the next couple weeks and make sure, but it looks like it's running fine right now, thanks for all the help! Later Dr. Evil........

ah what it sounds like then is the ram is being set for tighter timings at auto or is vdimm related. As the auto for vdimm is more then likly setting them to 1.8v when they need higher. set them manually and go back to ddr2-800 speeds.
also can you post a link to or tell me the modle of the ram you have. For instance like i have some corsair ram the model for it is CM2x1024-6400C4.

Now if im right and i found the correct model by looking over corsair's site the ram you have is JDEC rated for 5-5-5-12 @1.9 volts. but the ram is programed for 5-5-5-15. while the label is for your ram is correct some mobo's dont like the slightly tighter timings. To make them play nice they loosened them up so you have to manually set them.

I'm going to set the timings and such manually and memtest it overnight. The ram I have is 4 1GB sticks of the same Corsair as yours, without the C4 at the end. Since your ram is set to 4-4-4 and mine is set to 5-5-5-12.

This is the link to the ram on newegg:
http://www.newegg.com/Product/Product.aspx?Item=N82E16820145590

You can see the close up shot with the writing on the label.

Then on Corsair's website it says 5-5-5-15:
http://www.corsair.com/products/xms2.aspx

So which do you set the BIOS to? 12 or 15?

And yes I think the auto does put it at 1.8v.

Thanks a lot!

yea set your timings to 5-5-5-12 and voltage to 1.9volts.