Possible memory issue

[KeyboardDemon]

I had some Corsair RAM fitted in one of my PCs that was crashing, when I checked on MSI's website I could see the RAM I was using was not on their compatibility charts so I assumed it was down to that. I replaced that RAM with something that was listed as compatible. The RAM was not giving any errors on Memtest86, but the system was crashing when running games and even in Chrome, despite numerous fresh installs, this problem persisted until the RAM was swapped.

MSI config was:
MSI Z97 Gaming 5, i7 4790K (stock speeds), 8GB Corsair Vengeance (Part No. CMZ8GX3M2A 1866C9), GTX 780 Ti SC ACX, 850 watt PSU.

I replaced the 8GB RAM with 16GB (Part No. CMZ16GX3M2A 1600C10) which is on the compatbility chart.

Not being 100% certain if the RAM was OK or faulty, I put the RAM into my other rig:

Asus Z77, i7 3770K (stock speeds), 8GB Corsair Vengeance (Part No. CMZ8GX3M2A 1866C9), EVGA GTX 780 Ti SC ACX, 750 watt PSU.

I added the RAM from the MSI mobo in to the Asus mobo and now CPU-Z now reports two sticks of my RAM as PC3-10700 (slots 1 and 3) and the other 2 sticks as PC3-10700H (slots 2 and 4). Each pair has a slightly different timing configuration but the memory page on CPU-Z seems to suggest that all RAM is running at the speed of the slower sticks.

What's happening now, is that Chrome has become unstable and my PC is crashing out of games, which it wasn't doing before.

I've not run Memtest86, but will do so while I'm at work today, however, my question is, is this likely to be down to faulty RAM or just the H RAM not liking the non H RAM?

Whatever the reason, what can I do about it?

[Gronich26]

Remove the "known good" RAM from your Asus Z77, move the suspected faulty RAM into the slots you have removed the "known good" RAM and retest - This rules out a faulty memory slot & the two sets of RAM not playing together.

If you get the same crashes this definitely points to the RAM. However, I would check in the BIOS to see what setting the RAM IS running & find out from Corsair the settings it should be working at - If they are both the same RMA the RAM!

[Greybeard]

What's been suggested above is correct, test each set on its own and see which set of RMA will show its true color. Both RAM kits are compatible with that Z97 board and Z77 board, so its not a compatibility issue. I'd also recommend that you make sure that both board's BIOS is up to date and set everything back on default setting before proceeding to your testing.

Also note that, we technically don’t’ recommend mixing and matching sets of memory even if they have exact same part # (vendor) or even spec. We simply cannot guarantee one set of memory to work with another set, as these sets are not tested that way pre packaging. It is going to be a 50/50 chance due to some motherboard will let you do it and some boards are just pickier than others and this is the reason why DRAM vendors sells them in kits of a specific capacity. Also, each kit would be produce earlier/later than other, meaning BOM (Build of Materials) are going to be different from a kit that was built previously and a kit with the same spec that is currently in the market. This may cause the system to behave erratically when paired together. Best would be is to get a set of RAM that has the total capacity that you really prefer.

[KeyboardDemon]

What's been suggested above is correct, test each set on its own and see which set of RMA will show its true color. Both RAM kits are compatible with that Z97 board and Z77 board, so its not a compatibility issue. I'd also recommend that you make sure that both board's BIOS is up to date and set everything back on default setting before proceeding to your testing.

Also note that, we technically don’t’ recommend mixing and matching sets of memory even if they have exact same part # (vendor) or even spec. We simply cannot guarantee one set of memory to work with another set, as these sets are not tested that way pre packaging. It is going to be a 50/50 chance due to some motherboard will let you do it and some boards are just pickier than others and this is the reason why DRAM vendors sells them in kits of a specific capacity. Also, each kit would be produce earlier/later than other, meaning BOM (Build of Materials) are going to be different from a kit that was built previously and a kit with the same spec that is currently in the market. This may cause the system to behave erratically when paired together. Best would be is to get a set of RAM that has the total capacity that you really prefer.

I've decided to test both sets, running each set, one at a time for a few days in sockets 1 & 3 and then again in sockets 2 & 4, if all is well with each set, then they will go onto eBay and I will replace them with these. Should any appear to be faulty then I will RMA, but having seen that I have different revisions of the same part no. I was already starting to suspect the each set would work fine in isolation but then clash when combined with other RAM.

[Greybeard]

I was already starting to suspect the each set would work fine in isolation but then clash when combined with other RAM.

I am on the same boat with you on this one.