Ram Compatability - Upgrade

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do you mean compatible with adding the 2 8gbs modules with your existing 2 4gb modules? If so then you may have issues. It;s always advisable to buy in a kit of two matched DIMMS, which I presume your 2 x 4gbs are. By adding in the 2 x 8gb DIMMS you may have to do some tinkering to make it work.

I'd suggest just dropping the 2 x 8gb in, instead of adding to the existing ram. Sell the old ram to offset the cost of the new ram.

If it's for gaming only then having the 2 8gb in dual channel mode, with only 2 slots occupied will be better than having to mess around with timings from two different kits, and have 4 slots occupied.

If you want to add in the all the ram together, both sets would have to have the same timings, and voltage...
do you mean compatible with adding the 2 8gbs modules with your existing 2 4gb modules? If so then you may have issues. It;s always advisable to buy in a kit of two matched DIMMS, which I presume your 2 x 4gbs are. By adding in the 2 x 8gb DIMMS you may have to do some tinkering to make it work.

I'd suggest just dropping the 2 x 8gb in, instead of adding to the existing ram. Sell the old ram to offset the cost of the new ram.

If it's for gaming only then having the 2 8gb in dual channel mode, with only 2 slots occupied will be better than having to mess around with timings from two different kits, and have 4 slots occupied.

If you want to add in the all the ram together, both sets would have to have the same timings, and voltage, otherwise you will have a whole lot of playing around to try and get all for mixed DIMMS to work. I'm not saying they won't work, it will most likely be troublesome though.
 
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