So I found a seller of what appears to be the OEM RAM in the 751JT and possibly the JY, so if you wanted to upgrade to max it out and match the ram exactly this is what you would be looking at to get: Samsung M471B1G73DB0-YK0
http://www.amazon.com/Samsung-PC3L-12800-204-Pin-SoDimm-M471b1g73bh0-yk0/dp/B00J8U549K/ref=sr_1_1?ie...Seems like it may be a bit pricy but I haven't been in the laptop upgrade sort of area for a while, could be a fair price. Amazon.co.uk has two for 102 pounds or euros so it works out to the same there too.
Anyways, I think I read somewhere that these don't have built in graphics cards, rather they are actually proper cards that slot in, and could be upgraded though that would void warranty.
I'm wondering if anyone can confirm this? I think it may be a totally custom card though so it would be hard to get to do the upgrade unless you worked at a shop and managed to get a tracked JY and were able to use the card from that.