Well, depending on what u want there are quite a few options.

First I would check the warrenty on your current SSD, but if thats not good if u want a similar experience u chould check out the XPG GAMMIX S70 Blade 1 TB or the PNY CS3150 RGB 1 TB both are solid SSDs offer a DRAM Cache just like the 990PRO but both do have built in heatsinks so keep that in mind

Now if u want just a cheap replacement drive and dont mind not having a DRAM then maybe check out the XPG SX6000 Lite 1 TB as budget as it gets while still being of decent quality just be sure to put this one under a heat sink, now there are 2 other worth considering, the Patriot P400 Lite 1 TB and the Silicon Power P34A60 1 TB anything more that this and u should just get the 2 DRAM SSDs above