Very few games now support SLi and you might actually GAIN performance in games by getting rid of the 2nd 2080ti. SLi was such a huge boost of sales and marketing for nvidia a few years after they bought 3DFX, and in 2006 with the launch of the 6800U in PCIe allowed them to bring back the "SLi" name since it was property of 3DFX prior to nvidia buying them out and killing them. Steve, I wouldn't give bad advise.... other then benchmarks like 3dmark, and rendering software coded to use GPU acceleration, and few other niche software programs that can use SLi (some DX12 titles as well) SLi is actually hampering performance as it IS A HUUUGGGEEEEE driver overhead. Games just arent coded anymore and driver SUPPORT SUCKS SOMETHING TERRIBLE FOR IT! If you get board, pull the slave card out, and bench any given game that you actually "PLAY" and see where your FPS are at.. might be surprised by an actual frame boost. Worst case senario, you will see you were getting (for example 120fps with what ever game you bench) with BOTH cards in... remove 2nd card, Bench game again, and now you are getting 118FPS! Just saying... a $1000 GPU giving you an extra 2fps... see where im going here? I have a 2080ti as well in a 3950x build (obviously all watercooled with multi loops) Ive played with SLi for nearly every generation of nvidia GPU, and since Pascal... SLi support is just GONE!
EDIT.. also make sure you are using driver 445.75 or 445.78 as they introduced DLSS 2.0 with MASSSSSIVE GAINS of performance for titles that use DLSS.. So little heads up there. IF you still have my number, hit me up anytime if need any help