I find you get that a lot of the time, espically when some parts are not worth anything second hand or by themselves.
Things like a year old motherboard that was mid ranged or lower to start with. Generally worthless without a cpu. It still has a rrp, but not worth the time to remove from a existing computer.
Another is a year or two old power supply. While still good, some become more prone to dieing as they run out of warranty.
Lastly is cases. They have value to the right buyer, but given the size, taste and hassle of stripping a computer of of them, people are more likley to just part with them cheap.
The other side is that if you take a working machine, strip out the parts that sell well (cpu/gpu/hdd/ram), what you are left with for a lot of people is something that is close to worthless given the costs needed to get it working again.
That last paragraph is key. That's why I can "repackage" some old left overs that on their own are not enticing such as a 4-5 year old case that still has modern cooling, a near flagship 3-5 year old air cooler, 5 year old solid Corsair PSU, 1TB 7200 rpm old hard drive (but that's perfectly fine for storage of media) and drop in used after-market quiet 7970 and a modern i5/i7 and a get the latest "hot"0 $100 SSD (MX100) and now I have a system that's uber fast for 90% of buyers.
On their own, the old case, old PSU, 7970, 1TB 7200 rpm mechanical drive are not worth much. Who wants to buy a Thermalright Silver Arrow for $70 used when NH-D15/Corsair H100 is $90-100? Hardly many people. But for someone who doesn't overclock, an i5 4690K @ 4.5-4.7Ghz on Silver Arrow is worth $70-$100 more over a stock 4690K. That's how to sell an after-market cooler for $70 that you'd have no hope at all selling on its own in used form.
Now take those old parts and with an i5 4690K/i7 4790K OC, and get a new Crucial MX100 SSD, and people in a large city like Toronto would be all over that rig because it would cost a fraction of buying new parts. Not everyone can overclock or knows how to put together a solid system. All you need is just 1 interested person.
I've been reselling systems like this for at least 10 years. That's why I invest more $ into an after-market cooler and try to get a PSU with a 5-7 year warranty. If I have to upgrade, it'll be a breeze trying to sell an overclocked i5/i7 on Silver Arrow and SeaSonic Platinum even with an aged GPU because people know you can upgrade the GPU 2-4x over the useful life of an overclocked i5/i7 4xxx series while that cooler and PSU will keep the system bulletproof for 5+ years. I definitely changed my strategy for buying PC parts. The other huge advantage of buying a flagship cooler and PSU and a half-way decent case is that if you don't want to resell the CPU platform every 2-3 years, then these 3 parts will keep your system solid for years and years.
Nowadays, you can buy an i7 4790K or i7 5820K and overclock them and these CPUs should last 4-5 years allowing one to keep upgrading the monitor, GPU or SSDs only with little requirement to touch the CPU platform. Unless we see a sudden surge in CPU usage from PS4/XB1 console ports, the cost of PC hardware rig will dramatically decline since one no longer has to upgrade the case/PSU/cooler/CPU/mobo for 4-5 years for games. In the past, this was not possible.
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Getting back to GPUs, with lower nodes becoming
very expensive and a severe lack of any next generation PC games, I am looking to change my GPU upgrade strategy too. From reviews I have been closely tracking the longevity factor of NVs/AMD's 2nd best GPUs against the flagships. I have kept track of the following:
6800GT vs. 6800U
GTX 275 vs. 280/285
HD4870 vs. 4890
HD5850 vs. 5870
HD6950 vs. 6970
HD7950 vs. 7970
GTX 470 vs. 480
GTX 570 vs. 580
GTX 670 vs. 680
GTX 780 vs. 780Ti
R9 290 vs. 290X
^^ Not once in any of these generations, did the flagship product from AMD/NV last any longer for next gen games than the 2nd best from the top. The 10-20% difference amounts to almost nothing the minute a next gen game comes out that pummels the last gen flagship. For example, let's say a 780Ti OC now gets 70 fps in some title and 780 OC gets 60, in BF5, 780Ti OC will get 35 fps and 780 will get 28-29 fps -- both too slow. The obvious? Buy 780 for $450 and save $200 towards a next gen card when a game like BF5 comes out instead of "future proofing" with 780Ti.
Moving forward, I think buying NV's/AMD's second best card is a smart way to save money while hardly losing much tangible performance. And since SLI/CF is not 100% efficient, for guys going 2-3 cards, the difference is even closer since you'd apply ~ 90% factor to the performance of each setup, which brings the 2nd best cards even closer to the faster setup. A lot of people are eyeing the 880 but I think not enough credit is given to the 870 which could be a more preferable card overall
Ask yourself this, did 680 SLI last any longer than 670 SLI? Nope. Will 780Ti SLI last any longer than 780 SLI for BF5/Witcher 3? Doubtful.