I have a i5 Surface Pro 3 128GB and I have 31GB of music that I want to put on it. 71GB of my hard drive space is already taken up. My dad believes that if I put all my music on Surface that it will run slow. Has anyone experienced a slower Surface after filling up the hard drive space?
Sorry but the identified best answer is not correct. Filling up a drive is a problem with mechanical drives that then have to cycle to find stuff, access swap files, caches, etc.. It really is not 2004 - it 2014. Windows allocates the space for optimizations and caches at start up and once allocated there is nothing intensive about access on an SSD. As long as space exists for the caches, there is no concern and as it stands Windows 8.1 caches on Surface devices are tiny in comparison to previous versions of Windows.
In fact, sticking in a 64GB card is far more likely to slow certain things down because they do not run at the same speed as the SSD, memory, or other motherboard components. Yes, they are great for storage but moving frequently accessed things to such a card is not best for performance and never will be. MicroSDXC cards also, in my experience, have an annoyingly high failure rate, whether it be in my SP, SP2, SP3, original Surface RT, and my DSLR. Long and short of it is they have pushed the limits of technology. Yes, I do use a 128GB card and have used 64GB cards in the past but that is purely for storage, not any perceived performance improvement - the opposite effect is closer to the truth. BTW, if you want to test this, load a large complicated file on a card and on the SSD and see how long it takes to open from each.
Don't waste your SSD space but ask don't be concerned about performance hits from a past era with older technology. You would have to get down to a few GB of free space before you before it would be a potential problem. BTW, you can also set the essential cache to a fixed size which eliminates the prospect of using up its space....