A couple weeks ago I retired my old 3GHz overclocked Q6600 and upgraded to Intel's new flagship CPU i7 2600k. Now before I start writing up my very short opinion and review, those are the settings I still use in VirtualDub. Virtually nothing has changed. Even after more than 2 years, those settings are still the best in terms of "filesize:video quality"-ratio.
Encoding speed is measured in (average) frames per second. The more, the merrier. It's also important to know that there are, what I like to call, "motion-heavy" and "motion-light" scenes.
This is, like the name suggests, a scene in-game (or anywhere for that matter, but I'm talking video gameplay specifically here) in where there's either very much motion / moving happening on the screen or the opposite. Why is that important you ask?
Motion-heavy scenes take much longer to encode than motion-light ones, at least that was my experience in those 2+ years since. I might of course be totally wrong about this, and unfortunately I don't have hard statistics to show for, i.e. benchmarks while encoding. Just my observation, unfortunately.
This is of course explained as if you were 5 years old. There are much, much more complex processes going on during encoding which I won't get into because this article isn't about that. Please also bear in mind that I'm by no means an expert in video encoding. I do it as a private hobby and I say what I have observed.
Right, moving on then. A standard 10 min. uncompressed gameplay video recorded in 1920*1080 with FRAPS is about 20GB large.
When I was using my old, overclocked 3GHz Intel Quad Core Q6600, with the settings linked above, I encoded with about 8fps in motion heavy videos and about 13fps in motion light videos.
With my i7-2600k, clocked at stock speed, I average at 16fps in motion heavy videos and at 25fps in motion light videos. That's an increase of 50% in motion heavy scenes and 52% in motion light scenes.
For example my recent video was about 24GB uncompressed. And compared to action games there's not very much moving/motion happening in those 11 minutes. This video took me, with above linked settings, 15 min. to fully encode at average 24fps. The final size was about 200mb.
VirtualDub makes use of HyperThreading, while encoding, this is how my CPU load looks like. The blue bars are HT, the green ones cores.
Was the purchase worth it (for me)? Absolutely. If you, like me, are encoding quite a lot, the 2600k is a good choice. It brought me a huge boost in encoding speed and will save me a lot of time down the road. Not to mention it will encode even faster when I overclock my 2600k to 4GHz and beyond.
Unfortunately I've no access to a 2500k, so I can't compare the 2600k to the 2500k and see for myself how much better or worse the 2500k performs under the same set of circumstances. If I'd hazard a guess, I'd say not by a whole lot.
The 2500k is essentially a 2600k without the HyperThreading, and I don't quite believe HyperThreading alone makes up for the huge performance jump from Q6600 to 2600k. So if you don't care about a few dollars, get the 2600k. If budget is a priority, get the 2500k. Or wait for Ivy-Bridge CPUs, which will come out next year.