Buying a CPU… My 65W rule


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Or… Computing for tightwads

For my 6 yearly PC upgrade, how do I decide which CPU to buy? My pockets aren’t deep enough to simply buy the best there is, so price/performance is a major consideration.

The last CPU I purchased new was an Intel Core i3-xxxx. Even at the time it was towards the bottom of the pile.

I was playing a lot of Flight Simulator X at the time, and from what I’d read, it was a lot happier on Intel silicon than AMD, which I’d always been a fan of up to that point. Also, FSX only uses a single core, so it was important to get a high clock speed, and not important to get quad cores.

The top end Intel CPUs, with the ‘K’ suffix, meaning clock multiplier unlocked, have always commanded a much higher price. Too high for the extra performance gained, especially for those not interested in overclocking.

The i3-2130 at 3.40GHz was the obvious choice. It was in the price performance sweet spot.

Fast forward to 2019, and I’m playing Dirt Rally now and again. It generally runs great on the old i3, but there are occasional glitches - dramatic drops in framerate, which can be worrying when hurtling down a Hellenic mountainside. I’m also getting itchy for an upgrade, but to get an up to date CPU, I need to replace motherboard and RAM too.

For an interim upgrade I looked at the CPUs my motherboard supports. It supports both 2nd and 3rd gen Intel Core i-series chips, so I sourced an i5-3550 on eBay for £32. When I run the Dirt Rally benchmark again, I see no real difference in average frame rate, but the lowest framerate has dramatically increased. It barely hiccups now. It was likely Windows performing some background task that was causing the slowdowns, and adding 2 more cores made a dramatic difference.

But What Next?

Probably back to AMD. The Ryzen 5 3600 is looking good value, under £200, and is rated at 65W perfect for a tightwad.

*My self imposed 65W limit isn’t about running costs, it is simply a way to avoid getting carried away with buying the latest and greatest CPU in the range, and paying too much for the privilege. I also value a quiet PC, and the lower wattage devices help keep temperatures down even with stock or low cost coolers.