Solution
Ah, got it....

My system can run 1066Mhz, 1333Mhz, or 1600Mhz (Intel i7-950). I've run all three speeds, very little if any difference....(& yeah, 1600Mhz is touchy so I always run 1333Mhz....)

BUT, I've run AMD Phenom II X2 550's vs AMD Athon II X4 630 no contest, the four (4) cores really make a Noticeable difference.... (and Phenoms are 15--20% faster than Athon's...)

4GB vs 8Gb is supposed to be a bit faster too.... (haven't run this myself I run 6Gb & there isn't supposed to be much of an advantage to goto 12Gb, so, I haven't...)
The RAM will have specifications stating the Voltage, Timings and speed. be sure to go into system BIOS and set the speed, timing and voltage to those specifications. Powering four DIMMs as opposed to one, two or even three may require the voltage to be raised 'a notch or two'. Increase the RAM voltage in BIOS. The motherboard manual has a section dedicated to BIOS and BIOS settings. Look there for a description on how to adjust the voltage, etc.
 

jb6684

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What is the Exact model of RAM you are using? (send a NewEgg.com link to it....)
- need to know specs for both sets of RAM.... (mixing brands or versions isn't usually a good idea, BUT, let us know & should be able to get it running)

What can happen with "mixed" RAM types is the motherboard BIOS automatic settings can be fooled, then things don't work correctly (wrong voltage, wrong timings, ... etc..)

 

stick4gbpackers

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http://www.newegg.com/Product/Prod [...] 6820104073
http://www.newegg.com/Product/Prod [...] 6819103846
http://www.newegg.com/Product/Prod [...] 6814102843

I have 2 kits of KHX8500D2K2/4GB (2 x 2GB)
mobo: ASUS M4A785-M
CPU: AMD Phenom II X2 555 Black Edition
 
The voltage requirement for the Kingston RAM is 2.3v. The MB is likely defaulting to JEDEC standard specifications which would be 1.8v. Not enough power for that RAM. In Bios try:

RAM voltage 2.3v
Timings 5-5-5-18
Speed 800Mhz (the RAM is rated at 1066Mhz.)
 

jb6684

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If you download and install CPU-Z then look at the "SPD" tab you'll see the different 'specs' or JEDEC profiles for your RAM. I did check on the Kingston site, and, your RAM should work at the standard 1.8volts, it's just that it will only run at 800Mhz (and not the full rated 1066Mhz which requires the higher 2.2volts...)

I your case, your CPU can't seem to "Drive" four sticks. So, one somethings just a bit out of spec, either the voltage being supplied, the CPU or the RAM.

So, Badge has suggest the right fix:

RAM voltage 2.3v
Timings 5-5-5-18
Speed 800Mhz (the RAM is rated at 1066Mhz.)

http://www.valueram.com/datasheets/KHX8500D2K2_4G.pdf

"Each module pair has been tested to run at DDR2- 1066MHz at a latency timing of 5-5-5-15 at 2.2V. The SPD is programmed to JEDEC standard latency 800Mhz timing of 5-5-5-18 at 1.8V."

 
I have the same MB runing for probably a year. Getting eight gigabytes of DDR2 to run at that speed even if it is rated there is difficult, instability is the better description. I currently run the computer heavily with eight Gigabytes of DDR2 800 MHz. I increased the RAM voltage to 1.9-2.0v and overclock the PII 940 quad easily this way. So,

RAM your Kingston RAM voltage spec is 2.3v
Set the timings at 5-5-5-18
Set the RAM speed at 800Mhz. (the RAM is overclockable to 1066 Mhz. but the MB's VR's cause instability trying to run eight gigs at 1066Mhz. This problem with the 785G micro is well documented.
 

stick4gbpackers

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OK; I realized that I had to use an AM3/AM2+ CPU to get the mobo to do the 1066 speed.
What I've done so far...
Replaced my AMD X2 socket AM2 5400+ Black Edition with an AMD Phenom II X2 555 Black Edition (socket AM3) [unlocked all four cores]
removed/replaced CMOS battery
tried to change voltage but got scared when values were in YELLOW instead of BLUE... have it at 2.2-whatever now...

Since I now have a quad core, do I even need to concern myself with the memory speed difference?
Should I go back to "auto" (mostly) everything in BIOS, I have it at 5-5-5-18 and 1.8 voltage now?

Thank all for the replies, I must be "not as savvy" as I thought I was. :sol: Y'all have been great!!

It's running OK with 8 GB @ 800 speed, I guess that's the best I can do... Thanx again for the help!! :sol:
 

jb6684

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Ok, first mention of the AM2 5400+... Just to confirm; AMD Phenom II X2 555 would Not boot with 8Gb of RAM at Stock / "auto" voltage? AND, increasing voltage on RAM to 2.2volts Fixes the problem?

Next steps, both Intel & AMD cpu's have more trouble overclocking the RAM with four sticks rather than only two sticks.....I would stick with 800Mhz speed.

To wrap things up; I'd recommend running for a week at 2.2 volts. Then drop to 2.1 volts, run another week. Continue till you fail or reach 1.8 volts. I'd guess that things would be fine at either 1.9 volts or maybe 2.0 volts....

 

stick4gbpackers

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OK, sorry about not mentioning my old CPU, also I'm running W7 64-bit. Rite, 555 would not boot with 8 GB @ 1066, increasing voltage didn't help.
Found out:
1 - can only use 2 sticks/RAM @ 1066, period!
2 - 1066 can be a pain, better off running 8 GB @ 800Mhz.

So, it wasn't all me...
BTW, since I was able to unlock all four cores, system shows it as an AMD Phenom II X4 955;
Will the four cores speed up my system with 8GB RAM @ 800Mhz vs Phenom II X2 with 4 GB RAM @ 1066Mhz?

 

jb6684

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Ah, got it....

My system can run 1066Mhz, 1333Mhz, or 1600Mhz (Intel i7-950). I've run all three speeds, very little if any difference....(& yeah, 1600Mhz is touchy so I always run 1333Mhz....)

BUT, I've run AMD Phenom II X2 550's vs AMD Athon II X4 630 no contest, the four (4) cores really make a Noticeable difference.... (and Phenoms are 15--20% faster than Athon's...)

4GB vs 8Gb is supposed to be a bit faster too.... (haven't run this myself I run 6Gb & there isn't supposed to be much of an advantage to goto 12Gb, so, I haven't...)
 
Solution

stick4gbpackers

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OK, so I'm now running 8 GB RAM @ 800Mhz, with my Phenom II X4 955 CPU. My WEI is 7.3 for my CPU and 7.5 for my memory (overall 5.1), which I think is rockin' pretty good...

Thanks to all for the help, I don't know how to "close" this thread, but maybe someone else can benefit from my questions and the answers posted here. Y'all take care!