I use a 128GB SDXC card for my rBMP. Every download that is not a picture is stored on it. Also, I installed Diablo 3 on it and uses it for my software that are not on the Application folder. It's a 133x Lexar 10 card I bought for 80$ online. I have the base 2.3/256/8 rMBP which I use for few simple tasks. The idea behind the SDXC was to use it as a Windows 8 drive and leave the main SSD pure from all these Windows file that would fill up too much space. As I have yet to perform that install, I can not talk about the success of this operation. However, I have few comments / questions about it. - Diablo 3: Playing on it is fast and loading times, except the first one, are on par with what I would expect. Yet, lightyears away of my W7 SSD based gaming rig. It was hard to play while downloading, even when the launcher said it would be optimal. I noticed that if I download a torrent on it and watch a video stored on the card, it would skip frames. I think that is an issue with the band witch or controller, which can't handle many files at once. -Movies I watched Timescapes in 1440p on the card and never it lagged or took time navigate through the movie. Other 1080p films are playing quickly and load in VLC fast enough for not being annoying overtime. -Download I am not sure about this one, but it may be possible that torrent are performing poorly when writting on the card. I also think it may wear it very quickly. I'd rather wear it instead of my SSD so for 80$, I don't care, but that's something to think about if you invest in a more expensive, faster card. -Hardware The card can sometime get a bit hot, but it's not particularly noticeable as you have to pinch it to feel the heat. I think many people are aware of this, but the slot accepts only 60% of the card, the other 40% are left out. That's an issue, I have to keep taking the card out when moving my mac inside the sleeve. It fits but I'm afraid I'll bend it somehow. There's a promising kickstart; Nifty Minidrive which may be able to solve this, at the cost of having a restriction regarding the type of SDXC card (only microSDXC will do the trick, and they are slower and more expensive at the moment). As they reached far more than needed funds, I'll just wait to see what happens. Hopefully they will release it and it will keep up to the promise. Now, I wonder if this card is making my macbook acting like a fool: From the beach ball to the sleep bug, the very slow performance of some applications that are not located on the card, but needs to access to the path in order to store a downloaded file on it, I have so many issue with the rMBP that I can't believe it's not somehow my fault. I only installed few softwares, changed the resolution to 2880x1800 with RDM.app, and have the gfxstatus active. Are rMBP or cMBP notorious to act like fools when a SDXC is used for more than uploading/downloading pictures and video ?