Smikan, sorry to say but the v4 has been an extremely disappointing product. Your board may be only SATA II, but that SSD is performing at about 1/2 of SATA I speeds. An old Intel G1 SSD (without TRIM support) would perform much better than the v4.
You are not the only one with performance results like you have from the v4. So I can't say that anything you are doing is the problem. TRIM is enabled by default in Windows 7, and unless you disable it by using the CMD command line interface, it should be active. AS SSD shows us that you are using AHCI mode, with the Windows msahci driver, and that your SSD's alignment is correct, so that is all as it should be.
I think I see that the v4 is not your OS/boot drive, is it your data drive? If so, what do you store on it, not that should make a difference.