If your friends have the exact same hardware and drivers, and getting better performance then their ingame settings are different than yours.
I happen to be a great fan of both games and I have run them both on a i5-760 /(gtx760 and with an i7-5820K / gtx 980, so I know they are very demanding. I actually upgraded because of games like these. Eventhough you easily can get 50-60 fps with the first rig and the right settings, you can't avoid random fps drops and stuttering due to the lack of threads. Also you have to compromise a lot on the graphic side.
Gta v is so demanding that even with the Haswell-E system I can't run everything on full settings, this is especially due to the grass function which litterally suchs all energy out, I never have it above high. If you look at the dog, then you will see that its' fur is rendered hair by hair. Have a look at this site, where they explain graphic setting and performance impact.
http://www.gamersnexus.net/game-bench/1909-gta-v-graphics-optimization-guide
Watch dogs is a bit of a different story, because that game has had some serious driver issues, where its' performance is capped at 30 fps. If that's the issue I recommend you try some older drivers if it doesn't Work with the new one. Then again I will say that due to your 2gb graphic Card you cant go above medium setting, if you want a fluent gameplay.
I can see that the i3 gets nice fps in the techspot test, but it has been paired with a Titan x graphic Card, one of the planets most powerfull graphic cards. If you go back to normal setting you will see, that the r9 270 gets 52 fps, and thats with an i7-5960x (the octocore with 16 threads)). At the same time you have to be aware that these numbers are average, so it doesn't tell you how often og far it will dip below the smooth gameplay threshold of 40 fps. If you look at this metro last light test, you will see that your card spans between minimum 35 and max 57 on medium settings:
http://www.tomshardware.com/reviews/radeon-r7-265-review,3748-5.html
My best advice is to look at the optimization guide, if you want a better gameplay, with your current hardware.