I recently got a laptop (my first actually), and going over its capabilities, I noticed it only had a single stick of RAM in it. It is a Lenovo z575 with an AMD A6-3400m with Radeon HD 6520g APU, using 4GB DDR3 PC10600 RAM from Ramaxel. Based on the Windows Experience Index, I was getting the following results...
Gaming Graphics: 6.1
Finding out the benefit of dual-channel, I decided to get an additional 4GB (didn't have to be 4GB, but meh) of the same type of memory, but from Corsair. Installed it and ran the test again. Memory boosted to 7.3 (+1.4), Graphics boosted to 5.8 (+1.3), and Gaming Graphics boosted to 6.5 (+0.4). I was feeling quite happy about the result, but then decided to see what the results would be with just the Corsair stick in it. Come to find out, the only thing that changed was the Memory rating, which went back to 5.9. Seemed normal since it was now not in dual-channel mode, but the rating for Graphics and Gaming Graphics stayed the same. Seeing this, I did additional tests. I tested each stick individually, and together using the game Rift on Low Settings in the same exact spot for each test to see what fps I would get, and this was the result.
From the tests, the sticks individually made no change between the two, but both together made an improvement. From what I see just from a gaming perspective, I'm good to go with what I have. However, the result from the WEI continued to make me skeptical. If games were using the higher rated Corsair stick for graphics (since it is integrated) when both sticks were inserted, then why didn't the game results show even a little improvement of the Corsair over the Ramaxel? My thoughts tell me that game performance can only go as high as the lowest of both the RAM and Gaming Graphics (since I am running off an APU), so in the end, the rating for both sticks individually while gaming was 5.9. Gaming Graphics may have gotten a 6.5, but that was just for testing graphic capabilities and not mixed with RAM operations that games would do.
My question for everyone is what do you all think of this, and would the addition of a matching Corsair stick actually improve performance enough that it would be worth the cost of that additional stick?