GA-MA790FX-UD5P Trouble w/ 8gigs of F2-8500CL5D-4GBPK

[AJF]

Mobo: GA-MA790FX-UD5P with newest BIOS F5
Processor: AMD PhenomII X4 940 Black Edition
RAM: 2 sets of F2-8500CL5D-4GBPK (8gigs total)
OS: Windows XP-64bit

I have successfully installed 4 gigs (2 chips) of this memory at 1033Mhz running stable using the timings listed:

CPU Freq: 200Mhz
Mem clock: X5.33
DDR Voltage: 2.1V
NB Voltage: 1.2V

SPD values:
5-5-5-15
Command timing: 2T
TwTr: 4T
Trfc0: 127ns
Trfc2: 127ns
Write Recovery Time: 8T
Precharge Time: 3T
Row Cycle Time (tRC): 24T
RAS to RAS delay: 4T

However, when I install the 2nd set of memory to total 8 gigs, I get immediate errors in Memtest86+. I can successfully boot into windows and all 8 gigs are recognized by BIOS and Windows, but running Prime 95 gives numerous immediate errors. I've tried all these settings:

DDR Voltage: 2.1V
NB Voltage: 1.4V

SPD values:
5-5-5-15
Command timing: 2T
TwTr: 4T
Trfc0: 127ns (Have tried all of these up to 195ns)
Trfc1: 127ns
Trfc2: 127ns
Trfc3: 127ns
Write Recovery Time: 8T (max i can set to)
Precharge Time: 3T
Row Cycle Time (tRC): 24T (tried up to 42T which is max)
RAS to RAS delay: 4T

I have ran individual memtests with each stick, and they all pass fine. No matter what I have tried (increasing Trfc to 195ns, increasing tRC up to 42T, increasing NB Voltage to 1.5V) I consistently get many immediate errors when running memtest86+. It runs extremely stable with 4gigs at 1033Mhz, just can't get the full 8 gigs

Plz let me know if there is any more info you need from me and what can be tried to get this working right. Thank you.

[AJF]

BIOS pics

I took some BIOS pics. Despite my overclocking I have also tried to set back to standard Processor speed/HT settings and have not had any success. Also these pics were taken with only 2 sticks installed (though I changed the NB Voltage to 1.40V for the pic but didn't save/reboot so it is showing as 1.2V). First 2 are from M.I.T. Page (scrolled down for second pic), other 2 are from DRAM Config page.

[GSKILL TECH]

Try HT Voltage 1.40V, but if not, the CPU may be incapable of 4 modules at DDR2-1066, so I would suggest downclocking to 800 with 4-4-4-12 timings. This should be just as fast, without instability.

Thank you
GSKILL TECH

[AJF]

Thanks for your response. I tried turning up the HT voltage to 1.40v, but with no luck - same problem. I did clock it down to 800mhz at 4-4-4-12 and that seems to be stable so far with all 8gigs. How much slower is this than if I were running at 5-5-5-15@1033mhz? Also, what should the other timings be set to? Im using these at the moment but wondering if those can be tweaked for performance at 800mhz:

DDR Voltage: 2.0V
NB Voltage: 1.40V

4-4-4-12
Command timing: 2T
TwTr: 3T
Trfc0: 127ns
Trfc1: 127ns
Trfc2: 127ns
Trfc3: 127ns
Write Recovery Time: 6T
Precharge Time: 3T
Row Cycle Time (tRC): 25T
RAS to RAS delay: 3T

[GSKILL TECH]

They may not even be slower, they may even be faster than DDR2-1066 5-5-5-15.

Other timings are fine on AUTO, but what you have listed in fine. Simply set DDR2-800 4-4-4-12 2.0V and everything should be working well.

Thank you
GSKILL TECH

[AJF]

Thank you very much for your help. I was able to get my machine to run all 8 gigs at the speed/timings suggested and they ran with zero errors in memtest86+ for 12 hrs

This is the first time I am using GSKILL memory, and will definitely be a future customer largely to do with the great job of tech support you guys provide.

Thanks again!

[GSKILL TECH]

Glad to hear, enjoy!

Thank you
GSKILL TECH