Ram Crashing System

[canadianicon25]

setup:
vista ultimate 64bit service pack 1
intel D945GTP mobo ( latest bios installed )
pentium d 3.0GHz
100GB WD SATA HDD
Geforce 7600GT (latest driver installed )
Hercules Muse LT sound card ( latest driver installed )
Samsung DVD drive
Some generic CDRW drive
2x120mm fans
Sparkle power supply 400W

2 x 1GB patriot ( PSD21G8002H) w/blue heatspreader PC2-6400 5-4-4-14
2 X 1GB OCZ platinum (OCZ2P800R22GK) w/heatspreader PC2-6400 4-4-4-15

*could have the last timings reversed *

problem:

upredictable system hang or unassisted restart when all 4 sticks installed
stable system when only 2GB installed ( same brand or mix-n-match)
stable system so-far when only 3GB installed (asynch mode, would like to avoid)
no matter what the setup is bios reads memory okay
when all 4 dimm's installed, auto setting in bios sets timing to 5-4-4-13. have manually changed this to last vaule to 15; to no avail.
manually changed timings to 5-5-5-15 to run all memory slower; no solution

mobo req's 1.8V ram. patriot is 1.8V and OCZ is 1.9V. HOWEVER, when only both DIMM's of OCZ installed the system runs fine.

Please suggest anything. Hopefully all info is there. Let me know if you need anything else.

[jdrom17]

No idea what settings you have on that motherboard, but if you can, increase the northbridge voltage. Might be called MCH voltage or something like that.

I'm thinking that 4 DIMMs is just too much stress on the NB.

[canadianicon25]

No. I can't adjust any voltage values directly. I can do timing values and CPU mult. The weird thing is, maybe should have mentioned, this is not a new upgrade. The system was running with 4GB for ~4months then "all of a sudden" decided not to like it anymore.

[enaberif]

two brands of memory.
two different ways of setting up memory.

NEVER mix memory.

[canadianicon25]

there is only one way of setting up the memory. ram is ram; the underlying logic (functionality) is the same and it performs the same task. ram that will run at faster timings is capable of running slower. the problem is not mix-n-match ram. a chipset problem or damage to the DIMM sockets or mobo breakage is more likely.

[3.0charlie]

In theory, you are right. But in practice, you are wrong. We have a lot of experience with ram testing and it is a known fact across the enthusiast community that you cannot mix and match ram, both from different manufacturers and timings.

Either ditch a ram set and run 2Gb, or buy a second identical set to complement the first one for 4Gb.

[enaberif]

Originally Posted by canadianicon25

there is only one way of setting up the memory. ram is ram; the underlying logic (functionality) is the same and it performs the same task. ram that will run at faster timings is capable of running slower. the problem is not mix-n-match ram. a chipset problem or damage to the DIMM sockets or mobo breakage is more likely.

No.

Ram is not ram.

Some ram can run at 1.8v perfectl fine other types need 2.1v to run properly.

Usually running a 1.8v at 2.1v isn't a bad thing but it can be because if the memory can't handle those voltages your gonna kill it very quickly.

Second while some ram can run stable at 4-4-4-10 and other at 5-5-5-10 if you try running one brand at 4-4-4-10 it may need different voltage to run at 5-5-5-10 so again your taking a chance at ram becoming faulty due to running it the wrong way.

[canadianicon25]

do you know what it is that causes the errors, electronically speaking.

[enaberif]

Originally Posted by canadianicon25

do you know what it is that causes the errors, electronically speaking.

I just told you.

If you in advertently fry your ram it'll cause errors cause your system is now unstable.

[canadianicon25]

i didn't say that right. all of my ram still works. i can install the OCZ and patriot memory in any configuration up to 3GB and the system is stable. it's only when the 4th GB is added that things go wonky. i tried to narrow the problem down to a single bad DIMM or bad socket but there isn't one. is there something else that can go wrong when you have multiple ram IC's in close proximety to each other that come from a different manufacturor (excess capacitance, eletromagnetic interferance etc). That is what I meant by electronically speaking. I guess it is posed to someone with theory/design background.