Silver-based thermal grease is a top performer, but a lot of what's for sale is fake. Here are a few warning signs to look for:

• Low weight: Silver paste weighs about 2.5 times more than plain white silicone grease. If the specs say something like "contains 99% micronized silver", the extra weight should be obvious. Expect a mini-syringe of genuine silver grease to have a gross weight over 3-grams.
• Even, consistent color: Genuine silver grease is dark, filthy and muddy. The fake stuff looks attractive, shiny and spreads evenly, with no lumps.
• Low price: Silver is a precious metal, so silver paste should cost more than silicone based competitors.
• Generic (no brand name): Silver thermal paste is a top-of-the-line product. Of all thermal interface materials available, it's the least likely candidate for sale as a generic. Stick to established brand name products, like Arctic Silver 5, OCZ Ultra 5+, etc.

Q. I think the silver paste I used is fake; will it damage my hardware; should I remove it?
A. It shouldn't damage anything, so you don't have to remove it. It's still thermal grease, not mayonnaise. Of course, you won't get the higher performance you paid for.