Originally Posted by mdrejhon
(Only if you have a GOOD 1000Hz mouse, that does 1000Hz well and your motherboard isn't causing probs)
1000Hz has an additional advantage during VSYNC OFF ultra-highframerate gaming in many games such as older Source engine games:
Older Source Engine games often play at high framerates (e.g. 300fps), and here, 1000Hz mouse rates help a lot here. There's more position aliasing on a 500Hz mouse at 300fps, but less aliasing on a 1000Hz mouse at 300fps. (ever slightly less microstutters) This is easier to notice on CRT or LightBoost displays where microstutters are more visible due to the lack of motion blur.
When framerates fluctuate all over the map, 200fps, 300fps, 400fps, in older games, the errors of a 1000Hz mouse is smaller because the game can use the mouse position that is 1 millisecond "closest" to the specific frame rendered at that time. There's more mouse position aliasing with 500Hz during VSYNC OFF fluctuating-framerate use-case scenarios.
The minor aliasing between mouse positions and framerates, can yield very slight microstutters that feels like the difference between a higher-quality mouse and a lower-quality mouse. Most people don't notice since LCD motion blur often hides lots of microstutters, but CRT/LightBoost users can see the microstutters better.
By having framerates massively exceeding Hz, you minimize your input lag and you minimize tearing. At this point VSYNC OFF at ultrahigh framerates (e.g. 300fps or 400fps) looks kind of like as the perfect VSYNC ON scenarios (the framerate=Hz ideal test case, but without the input lag disadvantage of VSYNC ON). There is less input lag at 400fps@120Hz than 120fps@120Hz, since the frames are "fresher", rendered 1/400sec ago rather than 1/120sec ago. Framerates often seen by Team Fortress 2, Counterstrike payers... (older Source games).
-- If you play uncapped/fluctuating framerates at framerates massively exceeding Hz, 1000Hz actually can help rather than hurt in certain situations (unless it creates other problems that degrades accuracy from other causes to cancel out the 1000Hz advantage -- e.g. motherboard)
-- This is not always necessarily true if you lock your framerate. During that situation, using 500Hz or even lower may feel better.
All sorts of variables. Framerate caps can have an impact on your decision whether to use 1000Hz or not.