If your BIOS is using SPD (AKA auto) settings, 7-7-7-20 simply means you're running with a lower memory clk than the RAM is rated for. That shouldn't cause any problem or noticeable drop in performance. If you aren't using BIOS auto settings then enable them. Check what memory clk the board is using.
The RAM/mboard combo might still be unstable at default settings and might
need increased latencies to work. Before messing with that try these:
- disable anything labelled 'aggressive timing' (if present)
- disable spread spectrum options
- check the DIMM voltage is correct or on auto setting
- select 2T timing for RAM - big hit on performance but sometimes necessary
Also be aware that using 4 DIMMS can cause stability problems on many boards and is the most likely reason your memory is underclocked. The 1T/2T choice is most likely to help but the only fix may be removing 2 DIMMS.