It’s impossible to wrap this whole thing up in just five sentences. You really have to dive deep into the actual reviews for every new card that hits the market; you just can't judge performance based on a spec sheet alone. For instance, an HD 6950 2GB might boast a better memory bandwidth and more VRAM—it was practically $667 when it first launched—yet it performs on par with a Radeon RX 260 which has less memory and a narrower bus, but higher clock speeds. I guess the architecture and the efficiency of the processing units are just fundamentally different.
If you want a solid starting point, check this out:
1 x NVIDIA GeForce GTX 970, 256 bit, 1 x DDR3 8GB (2x4GB) Kingston, 1866MHz, CL10, Kingston Fury 1 x Intel Core i7-4790K (4.00GHz,1MB,8MB,88W,1150) Box 1 x Intel 120GB SSD 520, 2.5", SATA III-600, R/W:550/520MB/s 1 x HDD Seagate 1TB, Serial ATA III, 7200 rpm, ST1000DM003 1 x SCYTHE Mugen 4 SCMG-4000 1 x Corsair Carbide Series SPEC-02, ATX/Micro ATX, Blue LED 1 x XFX TS Series 550W PSU -P1550S-XXB9 1 x ASRock Z97 Extreme3, 1150, Intel ® Z97, DDR3, 4 slots
1 x AMD Athlon II x4 860 3.70GHz 4 cores, cache: 4MB 1 x DDR3 4GB (1x4GB) Crucial, 1600MHz CL11 1 x Intel SSD 120GB, 2.5", SATA III-600, R/W:550/520MB/s 1 x Asrock FM2+ Micro ATX 1 x NVIDIA Kepler Rev.2 cooler, 1156/775/FM1, 96.5×51×125 mm, 92mm 1 x MSI R7 260 OC 1GB GDDR5, 1GB DDR5, DVI-I, DVI, DP, HDMI, R7 260 1GD5 1 x Zalman Z1 mid tower case. 199(W)x432(H)x457(D)mm. ATX standard 1 x Fortron 500W power supply, Hyper-Threading, PPA5005003, 12cm fan
$1083
😛
The difference between the 260 and 260x models is mostly $50 when it comes to price, but honestly, the 260x just has slightly overclocked memory—maybe a 3-5% difference at most. I guess I'd rather have a better case and motherboard instead.
The Radeon R9 270X is basically just an overclocked Radeon R9 270 (we're looking at a 925MHz GPU on the Radeon R9 270 versus 1030MHz on the Radeon R9 270X). I guess they're using the exact same chips.
Head into your BIOS and bump the FSB from 200 up to 240, then set your CPU voltage to 1.350V before saving everything. You should probably run a stability test using Prime95 on the small FFT setting; I guess an hour or so would be enough. Just keep an eye on your temps—they really shouldn't climb past 60°C.
Like darkbadger12 mentioned, I guess you really need at least another 2GB of RAM and a decent cooler if you're planning on actually overclocking that CPU. You've got a top-tier motherboard there, which just means you have a massive bottleneck for that R9 280X.
Your GPU temps are high, sure, but they seem manageable. It’s entirely possible something else is overheating—maybe the processor? Plus, that new power supply doesn't look like much of anything special.
1 x GIGABYTE GA-970A-DS3P, AM3+ 1 x LC POWER LC-CC-97, socket 775/1155/1156/AMD 1 x AMD FX-Series X8 8320 AM3 Box 1 x Crucial 8GB DDR3 1600 Mhz (PC3-12800) CL11 1 x SSD Patriot Blaze R545/W430, 120GB, 7mm, 2.5" 1 x Zalman Z1, USB3.0 black, 2x120mm 1 x VC GAINWARD Nvidia GeForce GTX750, PCI-e, 1Gb GDDR5/128bit, 1085(1163)/2550MHz, mini-HDMI/dual-link-DVI-D/VGA 1 x Fortron Hexa+ 500W, 80+ 1 x HDD SEAGATE Barracuda (3.5",1TB,64MB,SATA III)
Total: $1578 Best Buy (free assembly and shipping)
A 120GB SSD for Windows and your apps, an 8-core processor—which I guess is faster than those i5s in several areas you mentioned—8GB of RAM, and a graphics card that might help with CUDA tasks or just casual gaming.
I've got an Inno3D GTX 760, and honestly, the temps aren't anything crazy... maybe 30°C at idle and 79°C under load with the fans spinning at about 36%.
Just one Intel Core i3-4160 (3.60GHz, 512KB, 3MB, 54W, 1150) Box processor. Just one stick of 4GB DDR3 Crucial RAM, running at 1600MHz with CL11 timings. I've got one Zalman Z1 mid tower case available. It measures 199mm wide, 432mm high, and 457mm deep, and it follows standard MB specs. Just one Toshiba 500GB hard drive—7200rpm, SATA 6 Gb/s, with 32MB cache (DT01ACA050). 1 x Fortron 500W Hyper power supply, PPA5005003, with a 12cm fan 1 x Asrock B85M-HDS - Intel 1150 Socket B85 chipset M-ATX mb $460
$865
I'm not entirely sure if upgrading to the i3 is actually worth it, especially since I can just overclock this G3258 up to 4.3 or 4.4GHz using the Spira Kepler. Since you can't overclock the i3, it might not be much of an improvement.
1 x GIGABYTE GA-970A-DS3P, AM3+ 1 x LC POWER LC-CC-97 cooler, compatible with socket 775/1155/1156/AMD 1 x Sharkoon VS3-V Chrome Tower, no PSU included, black, USB3.0 1 x Crucial 4GB DDR3 1600 MT/s (PC3-12800) CL11 1 x AMD FX X6 6300 3.5Ghz (4.1GHz) box 1 x Toshiba DT01ACA050 HDD (3.5", 500GB, 32MB, SATA III-600) 1 x Fortron Hexa+ 400W, 80+, active, 12 cm
They're probably too much for your processor, even if you manage a decent overclock... I'd suggest staying away from Asus cards, though; they usually end up being the most expensive option compared to other brands.