Mixing different amounts of RAM

[Autocon487]

So knew about mixing different rams from different brands is a bad idea. But I am not entirely sure how a 4gb and 2 8gb doesn't April together well. They are both a Patriot Signature DIMM DDR3 CL11 PC3- 12800 (1600 MHz). The difference is the memory module. 4gb is PSD34G160081, and the 8gb is PSD38G16002. Someone explain?

Thank you

 

[geofelt]

Ram is sold in kits for a reason.
A motherboard must manage all the ram using the same specs of voltage, cas and speed.
Ram from the same vendor and part number can be made up of differing manufacturing components over time.
Some motherboards, particularly AMD can be very sensitive to this.
This is more difficult when more sticks are involved.
That is why ram vendors will NOT support ram that is not bought in one kit.

Most of the time, disparate ram will work, so if you have both, go ahead and try them together.
Test with memtest86. You should be able to do a full pass with NO errors.

If you have a problem, test each stick individually.
If both work singly, try adding a bit of extra ram voltage in the bios.

With a 4 and a 8 gb stick,(on an intel processor) the first 4gb will operate in dual channel mode, and the odd 4gb will be in single channel mode.

 

[Autocon487]

Ram is sold in kits for a reason.
A motherboard must manage all the ram using the same specs of voltage, cas and speed.
Ram from the same vendor and part number can be made up of differing manufacturing components over time.
Some motherboards, particularly AMD can be very sensitive to this.
This is more difficult when more sticks are involved.
That is why ram vendors will NOT support ram that is not bought in one kit.

Most of the time, disparate ram will work, so if you have both, go ahead and try them together.
Test with memtest86. You should be able to do a full pass with NO errors.

If you have a problem, test each stick individually.
If both work singly, try adding a bit of extra ram voltage in the bios.

With a 4 and a 8 gb stick,(on an intel processor) the first 4gb will operate in dual channel mode, and the odd 4gb will be in single channel mode.

I am actually gonna upgrade my cpu to a intel core i7-4790k with a ASUS Micro ATX DDR3 1600 LGA 1150 Motherboard. So the 2 8gb and 4 gb won't have a problem on this system?

 

[geofelt]

Likely, not a problem, but that is not 100% certain.
If the 2 8gb sticks are from the same kit, they should work and give you 16gb.
If they are separate sticks, you may have a problem working together. A touch of added ram voltage in the bios my fix such a problem.
Once you get 16gb working, it will not hurt to install the extra 4gb. If you get it to work, you have 20gb.
The last 4gb will operate in single channel mode, but more ram is better.

 

[Autocon487]

Likely, not a problem, but that is not 100% certain.
If the 2 8gb sticks are from the same kit, they should work and give you 16gb.
If they are separate sticks, you may have a problem working together. A touch of added ram voltage in the bios my fix such a problem.
Once you get 16gb working, it will not hurt to install the extra 4gb. If you get it to work, you have 20gb.
The last 4gb will operate in single channel mode, but more ram is better.

Alright, so solving the problem with the system I have right now. Does this memtest86 help me find the problems and solve the solution?

 

[geofelt]

memtest86 will prove that your ram configuration is good.
If memtest86 fails, then you need to resolve the issue.

 

[Calvin7]

Patriot Signature 8GB 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model PSD38G16002
https://www.newegg.com/Product/Product.aspx?Item=9SIA4M55243070&Tpk=9SIA4M55243070

Modules sold as singles are not intended to be combined. Using multiple modules is not guaranteed to be compatible. Adding another 4GB module is also not guaranteed to be compatible.

Memory is guaranteed in the form it is sold. A module sold as a single is guaranteed for life to work to specifications as a single.

Combinations such as you are making are done on a "do it yourself" compatibility testing basis. Since the modules have never been tested together, there is no guarantee they will work together.

Workarounds to get extra memory to work together include:
Lower DRAM frequency
Raise DRAM voltage
Relax DRAM timings
Lower CPU multiplier

MemTest86 tests for defective memory.

 

[Autocon487]

memtest86 will prove that your ram configuration is good.
If memtest86 fails, then you need to resolve the issue.

Thank you for the help. Ill try to resolve my issue and maybe let you know if it worked or not