athonline :
I got a feeling that G. Skill Trident-X 2400MHz are just a factory overclocked version of the Trident-X 1600MHz, as they run on 1.65V compare to 1.5V.
That is what I am telling you. There are only very few manufacturers of DRAM chips left on the market, so all DIMM manufacturers have to buy their chips from these and solder them upon their DIMMs. Trouble is, there are no 2400MHz chips being manufactured, so all the DIMM manufacturers like G.Skill can do is put the chips they are buying on a test bench to see how far each one can be overclocked and overvolted and then make factory-overclocked 2400MHz DIMMS out of them.
Note that power consumption (= heat emission) rises linear with clock speed and even square with voltage. You can imagine what this means for the DIMMs. That is why those overclocker DIMMs typically have those fancy coolers on them. German c't magazine recently tested them though and stated that these coolers do nothing to keep the chips cooler and just serve to keep them from sight, making your module look better and preventing you from being able to read the imprint on the chips (so you cannot look up their type and find that they are overclocked 1.5V chips). Of course real coolers could help, but there is too little space between the modules to allow for decent coolers. Some of those "coolers" actually cause the chips to become hotter than they would be without.
athonline :
I am wondering if I should just OC mine further to 2400MHz and call it a day or return them in favour of the "native" 2400MHz RAM.
There are no native 2400MHz RAMs.
As for the performance improvement, those WinRar numbers look impressive, but that is because Winrar compresses large files, so a lot of uncacheable data needs to be fetched from the RAM. Even hard disk speed could be a bottleneck here, but I suppose Windows (or the testers) made sure the data is loaded into memory up front.
So if you are zipping files, there is a noticeable gain. Question is, how often are you busy zipping files, and does zipping files comprise a noticeable part of the time you spend at your computer? I guess not.
More interesting are the gaming tests, especially those with separate GPU (no halfway-serious gamer in his right mind would game on an IGP). There you find that the difference between the slowest, crappiest settings and the fastest, hardest overclocking settings are like 1%. Depending on the game, there is sometimes no gain at all.
This is not surprising, because modern CPUs have very elaborated cache systems (with cascaded 1st, 2nd and 3rd level cache) and advanced prefetch algorithms that make sure the required data is not loaded from RAM, but already sitting in the CPU cache in almost all times (or already being prefetched from RAM while the CPU is still busy processing preceding commands).
As the consequence, overclocker RAM means a lot of power consumption, a lot of heat in the case, a lot of hassle because BIOSes often fail to apply the right settings (even with XMP), and even more hassle because these overclocked modules often do not work as they should. And for what? 1% gain? For that you pay a significant amount of additional money for your memory modules, money that could as well go into a faster-clocked CPU or GPU? Does not make sense to me.