A:Answer If the model number you're referencing is G74SX, according to the compatibility checker on Crucial's website (crucial.com), this is *technically* compatible with your system...however, since the limit of your motherboard is either 8 or 16GB, this single 8GB module is overkill and may not work alone (some systems require pairs of memory modules).
If you have the dual-core version of the G74SX, it looks like the max supported RAM is 8GB (and there are two slots) and if you have the quad-core version of the G74SX, the max supported RAM is 16GB (and there are 4 slots).
In order to best use what is available, I would recommend purchasing the linked item (SKU: 2824528)....one pack if you have the dual-core G74SX, or two packs if you can and you have the quad-core G74SX. This will allow you to replace whatever is there and install the maximum amount of RAM possible.
Hope this helps!