FPS itself has no actual direct impact on DPS, however, low FPS is an indication of poor computer performance in general. As a side effect your computer is spending significantly more CPU cycles trying to process the graphics than it is processing your actions. Low FPS doesn't lower your DPS because FPS is low, it lowers your DPS because your computer is too busy trying to draw a screen that it hasn't gotten to the point of processing your key press yet. You can't actually measure the impact of FPS on DPS because it will vary from machine to machine based on how it prioritizes your hardware interrupts over the actual game display.
Latency however does have a measurable impact on DPS, and improving it will improve your DPS. This is most obvious in the form of the GCD. While your GCD may only be 1 second, if you're latency is 250ms, it takes you 1.25 seconds at least to do your next ability. Abilities longer than the GCD don't have the same issue because of how spell queuing functions and how the GCD is tested. By lowering your latency from 250ms to say 100ms, you effectively turn that 1.25 second GCD into 1.1 seconds allowing you to DPS 12% faster than you were before (at least in regard to instant cast abilities). That is a huge increase in DPS for melee classes in particular. Ranged classes benefit from it as well, but not on the same scale.
Something else to keep in mind is your latency varies over time (hence that Quartz casting latency indicator). That tells you what your latency was on your last cast. You're screen may show 100ms, but you may actually vary between 100ms and 200ms in actual application. In any case, lower is always better.
One of the easiest ways to improve this is to adjust your TcpAckFrequency on Windows machines. You can either do this directly yourself through the registry editor, or can use an third party tool like Leatrix.
Last edited by Quinafoi; 09-07-2010 at 09:20 AM.
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