For any locked 1150 socket build (no CPU overclocking) and any single GPU configuration (again, at factory clock speeds), there is absolutely no need for anything more than a well made 450W PSU. If you want some evidence to support this, look at some of the official Steam Machine's. 450W PSU's are commonplace even when paired with GTX780Ti's.
Even running Prime95+Furmark an 1150 socket system with an i5 and a GTX780 is only going to pull ~400W from the PSU. Any well made PSU in this class will have ample overhead already built into the design, so there's no real need to oversize any further than this. The SuperFlower made Capstone 450W is always my favorite pick for any non-OCing 1150 socket single GPU build.
Most multiplayer/online games are compute intensive more-so than render intensive. The CPU will set the tone for performance more often than any other component and as mentioned previously, many of these games will not scale into many-core designs very well. The result is that like most compute intensive games, performance scaling beyond a quad core is not very good. The result of this, is that the best value for performance in these games lands on the i5 haswell group of products. The i5-4590 is typically the best value among them. (though current pricing on the $4690K is only $20 more, so this is an option, even if it won't be overclocked, to buy some higher clock speeds).
Compute intensive DX11 games will run better with Nvidia's proprietary DX11 API. The vast majority of modern "online" games will fall into this category. The reduced compute overhead afforded by NVs proprietary API here actually improves CPU related performance issues.
If you've ever felt how hot a motherboard can get around the VRM area when the CPU is under heavy load, even on stock clocked systems, you'd realize it's not a bad idea to pick a board with a heatsink on the VRM mosfets, even if it's not intended as an overclocking board. This will reduce the localized temperature extremes/swings, which should improve the life of the motherboard.
When picking memory for a system that is anticipated to have high compute workloads with lots of memory access (gaming
😉 ), the best memory access performance will come from a dual channel, dual rank memory kit that matches the highest supported speed of the memory controller with the tightest possible timings. In the case of Intel "locked" builds, that would be something like a dual channel, dual rank (16 X 8 bit components per dimm) kit of 1600-8-8-8 or better.
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The following builds are priced out based on the assumption that MIRs are a scam that you should not participate in or encourage.
PCPartPicker part list /
Price breakdown by merchant
CPU: Intel Core i5-4590 3.3GHz Quad-Core Processor ($198.98 @ SuperBiiz)
CPU Cooler: Arctic Cooling Freezer i11 74.0 CFM CPU Cooler ($23.98 @ Newegg)
Motherboard: ASRock H97 PERFORMANCE ATX LGA1150 Motherboard ($89.99 @ Newegg)
Memory: Mushkin Blackline 8GB (2 x 4GB) DDR3-1600 Memory ($86.99 @ Newegg)
Storage: Crucial MX100 256GB 2.5" Solid State Drive ($109.99 @ Amazon)
Video Card: MSI GeForce GTX 660 2GB Video Card ($172.98 @ SuperBiiz)
Case: Fractal Design FD-CA-CORE-3300-BL ATX Mid Tower Case ($44.99 @ Newegg)
Power Supply: Rosewill Capstone 450W 80+ Gold Certified ATX Power Supply ($59.99 @ Amazon)
Total: $787.89
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2014-09-04 12:27 EDT-0400
If you can scrape together an extra ~$100 make the following changes:
PCPartPicker part list /
Price breakdown by merchant
CPU: Intel Xeon E3-1231 V3 3.4GHz Quad-Core Processor ($247.98 @ SuperBiiz)
CPU Cooler: Arctic Cooling Freezer i11 74.0 CFM CPU Cooler ($23.98 @ Newegg)
Motherboard: ASRock H97 PERFORMANCE ATX LGA1150 Motherboard ($89.99 @ Newegg)
Memory: Mushkin Blackline 8GB (2 x 4GB) DDR3-1600 Memory ($86.99 @ Newegg)
Storage: Crucial MX100 256GB 2.5" Solid State Drive ($109.99 @ Amazon)
Video Card: EVGA GeForce GTX 760 2GB ACX Video Card ($239.99 @ Amazon)
Case: Fractal Design FD-CA-CORE-3300-BL ATX Mid Tower Case ($44.99 @ Newegg)
Power Supply: Rosewill Capstone 450W 80+ Gold Certified ATX Power Supply ($59.99 @ Amazon)
Total: $903.90
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2014-09-04 12:23 EDT-0400