The lists on Intel's pages aren't all-inclusive, they're just memory that Intel has tested and verified in their lab. You should be ok as long as you stick to the basic requirements listed on Intel's support page:
- Supports two 1.5V DDR3 or 1.35V DDR3L (low voltage) SO-DIMMs
- 1333 or 1600 MHz
- Unbuffered, non-ECC
- Minimum recommended memory: 1 GB
- Maximum memory: 16 GB
- Serial presence detect (SPD)
I have the model you listed, and I've tested it with several different types of memory. Right now I have:
Kingston KVR1333D359/4G 1.5v
I have also used Patrio PSD34G133381S 4GB PC3-10600CL9
Both work perfectly. Newer memory (as long as it meets the listed specs) should also work fine.
Incidentally, if performance is a factor you may want to consider a pair of DIMMs rather than a single, larger one. You get a bit better performance with a pair installed.
I hope this helps.
Yes, you can mix different speeds. It just means that both will run at the slowest speed. So in your case both will run at 1333. To get the most benefit out of dual dimms you want to match them as closely as possible. If you're looking to go to 16 GB total, you'd want to get a similar 8GB DIMM. I know you said there wasn't much on it in the way of labeling, but does it at least say the brand? Any chance you could post a picture of both sides?
If you can't find any more information on it, you can just get another 8GB 1600 DIMM and it will likely work fine.