Similar model Different version, incompatible with system

I recently purchased 2 sticks of XMS3 4GB(1x4GB) 11-11-11-30 1.50v ver2.13, these 2 RAM work perfectly in my system without a problem.

I was hoping to expand my memory again with another 2 sticks of what I believed to be the same memory, but when trying to use either of these it does not even allow the hard drive to start the boot process, XMS3 4GB(1x4GB) 11-11-11-30 1.50v ver7.21

The only difference between these 2 is the version number, could this make such a big difference? If so is it possible to be able to get the previous version?

I was hoping to expand my memory again with another 2 sticks of what I believed to be the same memory, but when trying to use either of these it does not even allow the hard drive to start the boot process, XMS3 4GB(1x4GB) 11-11-11-30 1.50v ver7.21

As Synthohol has stated Corsair does not suggest or support mixing memory even if they are the same exact part number. Even two single sticks as you purchased can be incompatible with each other.

However, the issue with your system and the memory is the version or construction of the modules. Your system needs memory that is constructed with 256mb IC's and the version 7.21's are made with 512mb IC's making them too dense for your MB to see and why your MB wont boot with them in.

So they would be incompatible.

he only difference between these 2 is the version number, could this make such a big difference? If so is it possible to be able to get the previous version?

Unfortunatly most of Corsairs memory would be made with the 256MB IC's and there is no way to specify version umber when ordering.

Just about all other manufacturers have also moved to the larger IC's so getting memory for that aging system may be tough. Might want to think about a new MB/CPU instead of trying to find components for that system.