Computer memory

[FHSPSU67]

A little more than a month ago I upgraded my Gateway FX542X's memory from 4GB to 8GB - I have Vista Ultimate 64-bit. I bought the memory from Crucial.com and they recommended PC2-8500's over my original PC2-6400's.

After about 10 days my system began freezing up and refusing to boot until I played around with it - at one point upgrading my video driver. The "fix" would always last 8-9 days and then crash. The last time it crashed I couldn't even boot in Safe mode, so I reinstalled my original 4GB and everything's been fine for the last 3 days.

Crucial states that the 8500's should be backward compatible and that I probably have one bad chip (of 4). Gateway says that my system will not work with 8500's although I've read that 8500's should be backward compatible.

Any ideas or discussion welcomed:)

[Greg Alsobrook]

1. Run the system with 3 sticks at a time for at least 10 days... see if you have any feezeups... If so, start rotating the sticks around to determine which one is bad... If not, the bad one is likely the one you didn't put in...

2. Try running MemTest86 (http://www.memtest86.com/) with just one stick at a time...

3. Send all 4 back for new ones...

[kokishin]

A little more than a month ago I upgraded my Gateway FX542X's memory from 4GB to 8GB - I have Vista Ultimate 64-bit. I bought the memory from Crucial.com and they recommended PC2-8500's over my original PC2-6400's.

After about 10 days my system began freezing up and refusing to boot until I played around with it - at one point upgrading my video driver. The "fix" would always last 8-9 days and then crash. The last time it crashed I couldn't even boot in Safe mode, so I reinstalled my original 4GB and everything's been fine for the last 3 days.

Crucial states that the 8500's should be backward compatible and that I probably have one bad chip (of 4). Gateway says that my system will not work with 8500's although I've read that 8500's should be backward compatible.

Any ideas or discussion welcomed:)

Is the BIOS auto-configuring the DRAM?

[FHSPSU67]

1. Run the system with 3 sticks at a time for at least 10 days... see if you have any feezeups... If so, start rotating the sticks around to determine which one is bad... If not, the bad one is likely the one you didn't put in...

2. Try running MemTest86 (http://www.memtest86.com/) with just one stick at a time...

3. Send all 4 back for new ones...

Is the BIOS auto-configuring the DRAM?

Greg, I got pretty much the same advice from Crucial. Do you agee that PC2-8500's should work and Gateway is CYA'n?

Kokishin, I'm not positive of this. I know there are options, but I'll have to get back here after examining my BIOS.
[edit] Yes, it is set to AUTO.

[FHSPSU67]

1. Run the system with 3 sticks at a time for at least 10 days... see if you have any feezeups... If so, start rotating the sticks around to determine which one is bad... If not, the bad one is likely the one you didn't put in...

2. Try running MemTest86 (http://www.memtest86.com/) with just one stick at a time...

3. Send all 4 back for new ones...

End of story: I checked all 4 sticks individually - all passed but no combination would boot. Called Crucial and they are sending me PC2-6400's. I also found a motherboard spec on the web that indicated no PC2-8500 capability. Thanks, all!

[Stewart Vernon]

It has been a while since I read up on all the various memory sticks available so I'm unfamiliar with all the specs... but on the surface the "backward compatibility" thing sounds suspicious to me.

I've seen far too often where the newer RAM would require less power than older RAM, and if your motherboard/BIOS wasn't designed to handle that, then the RAM wouldn't work.

I also happen to have two PCs. They are older ones... but one needs PC100 ram, while the other wants PC133. Yes, they are old! But even though both are IBMs made within a year of each other... I can't swap the RAM between them. It just doesn't work.

So I wouldn't be surprised in your situation if Crucial is wrong, so hopefully the new RAM will do the trick once you get it.

[FHSPSU67]

It has been a while since I read up on all the various memory sticks available so I'm unfamiliar with all the specs... but on the surface the "backward compatibility" thing sounds suspicious to me.

I've seen far too often where the newer RAM would require less power than older RAM, and if your motherboard/BIOS wasn't designed to handle that, then the RAM wouldn't work.

I also happen to have two PCs. They are older ones... but one needs PC100 ram, while the other wants PC133. Yes, they are old! But even though both are IBMs made within a year of each other... I can't swap the RAM between them. It just doesn't work.

So I wouldn't be surprised in your situation if Crucial is wrong, so hopefully the new RAM will do the trick once you get it.

Thanks, Stewart:) They should work because the original 1GBx4 PC2-6400's have been flawless. I bought this Gateway in January 2009.

[elaclair]

I also happen to have two PCs. They are older ones... but one needs PC100 ram, while the other wants PC133. Yes, they are old! But even though both are IBMs made within a year of each other... I can't swap the RAM between them. It just doesn't work.

So I wouldn't be surprised in your situation if Crucial is wrong, so hopefully the new RAM will do the trick once you get it.

Stuart, in the case of the PC100 vs PC133, there are significant voltage and pin differences, so there would be no possible backwards compatibility there.

Now PC266 vs PC133 should have backward compatibility, but you may run in to timing problems, which is what I suspect is the problem the Gateway is having with the higher speed rated RAM.

[Stewart Vernon]

Stuart, in the case of the PC100 vs PC133, there are significant voltage and pin differences, so there would be no possible backwards compatibility there.

Now PC266 vs PC133 should have backward compatibility, but you may run in to timing problems, which is what I suspect is the problem the Gateway is having with the higher speed rated RAM.

I probably overly abridged that post... The true truth is that the RAM sort of works one way but not the other. I have a 256MB DIMM that works in either computer, for example, but a 128MB DIMM that only works in the older computer.

In any event, I know sometimes RAM is more similar than others... I've just lost faith that when someone sells something and says "sure it'll work" that I do some research first to see if that is possible or not.

I do know sometimes you can, but when you can't it's a pain if it leaves you hanging.

[P Smith]

Each SO-DIMM/SIMM/DDRx have small EEPROM chip with SPD info; BIOS will read it and would verify that data against own tables. You can find short info about your DIMM by run CPU-Z program from cpuid.com
There are a lot of programs what will tell you about each bit in that SPD, some of them could change it.
As to a claim "in the case of the PC100 vs PC133, there are significant voltage and pin differences, so there would be no possible backward compatibility there", it's been wrong. Those SDRAM pretty close to each other and often PC133 will works instead of PC100 ( if your BIOS is not that stubborn). But PC266 and PC133 pretty far of each other - I bet they wouldn't be interchangeable.