Mixing Aegis & Ripjaws

[Serville]

I have Z68 board with 2 x 4GB Ripjaws DDR3 on slot 2 & 4 (With XMP Profile 1 on my Biostar TZ68K+).
I'm thinking of buying another pair of 2 x 4GB Ripjaws, but somehow the price has increased so much lately (about $16 more expensive than Aegis), and it's also out of stock.

How critical is it to match RAM in all 4 slots ?
Could I just buy PC12800 AEGIS single channel , which is quite cheaper (& available) than Ripjaws and use it on Slot 1 & 3 ?

So, it will become :
- Slot 2 & 4 Ripjaws PC12800 4GB
- Slot 1 & 3 Aegis PC12800 4GB

I notice that the RAM tming is the same 9-9-9-24 for both Aegis & Ripjaws.
Will I gamble too much?
I suppose the single-channel Aegis on Slot 1 & 3 will give me dual-channel ?
Will I have problem running the same XMP Profile ?

[Serville]

Oops sorry. I just realize Aegis has different timings from Ripjaws

But what if I buy F3-1600C9D-8GAB Ares 2x4GB to the second channel instead, while Ripjaws on the other channel.

Ares F3-1600C9D-8GAB : 9-9-9-24-2N 1.50v
Ripjaws F3-12800CL9D-8GBXL : 9-9-9-24-2N 1.50v

They have exactly the same timings.

[emissary42]

Regardless of manufacturer the general consensus is that mixing kits is not recommended, even though it sometimes works. Also while the primary timings might look identical, there could be differences on the secondary side. That is for example also the case between single and double sided kits of the same model.

[HARDCORE GAMES™]

Try JEDEC standard timing for DDR3-1600 which is 11-11-11-28

I have managed to get mixed RAM working with JEDEC timings fine