Hardware: Picking a New CPU for Second Life


The letter at the end of i5-6600K name is about some options built into the CPU. The ‘K’ designates the CPU as having an adjustable clock. The CPU is rated to tick 3.5 billion times per second (3.5GHz). Because my CPU has that ‘K’ in the designator/name I can adjust the speed of the clock. Adjusting the clock to tick faster than 3.5GHz is called overclocking.

I tried running mine at 4.4GHz and I kept crashing. I slowed down to 4.1GHz and things seem to work OK. No crashes since the change. I’ll probably play with that and try 4.2 and 4.3. It can get really complicated. If I change clock speed and voltages in the CPU, I could probably push it back up to 4.4 or 4.5. But, I find that tedious.

Do we need to overclock for Second Life? No. I get a pretty consistent 60 to 80 FPS at 4.1Ghz. If I slow down to 3.5GHz, that would theoretically be a 15% decrease. 60FPS x 85% = 51FPS. How much difference does 9FPS make? For any practical or noticeable difference at this speed, none. We are talking a difference of 3ms per frame, well below human perception.

I overclocked this computer because I have more video work to do these days and it can shave significant time off some tasks. It doesn’t do much for SL.

CPU Cooling

If you run at factory speeds – no overclocking, CPU’s cool well using the typically included fan and heat sink. But, those combinations are designed with the typical home configuration and competitive cost in mind. Think: make it cheap.

Ninja 3B Heatsink on ASUS z170-A motherboard - initial test

Ninja 3B Heatsink on ASUS z170-A motherboard – initial test

Gamers tend to push things. Running render-intense games like Second Life is pushing things. Your computer and in particular your CPU is likely to run hot even when not overclocked. Running hot shortens the CPU’s life. When a CPU dies it can take the motherboard and there is no telling what a dying motherboard will take out as it goes. So, avoid overheating.

Fortunately, ‘destructively hot’ in the case of a CPU is really ‘hot’ and CPU’s have built in heat protection to avoid self-destruction. They will slow down processing (tick slower) to draw less current and avoid overheating and turn off if necessary. So, cooling is more about maintaining speed than protecting the CPU from destruction.

If you look at the image of the viewer and hardware monitor again the monitor shows my CPU is running cool, 45C or 113F. My old Quad Core2 often ran at 70C or 158F. When I would forget to clean it I would catch it at 80+C or >=176F, way too hot and the CPU was throttling back slowing me down, which was why I was looking and caught it. I have not seen my i5 get to 70C.

I put a big heatsink on my CPU. The image shows it. A Ninja 3b (US$55). I am installing it before installing the motherboard in the case, much easier and still not all that easy. I’m testing the setup. The CPU cooling fan I leaned against the heatsink for this test. Clipping it in place is a REAL pain… or I haven’t figured out the easy way. But… Yay, I was so happy it tried to boot. My first motherboard was defective and wouldn’t pass POST (Power On Self Test).

Do you need a big heatsink to run Second Life? No. But, it doesn’t hurt.

Use a hardware monitor to see how hot your CPU runs when running a viewer. Somewhere over 65C consider cleaning your computer’s heatsink or getting a bigger and better heatsink.
More pages, links below…

4 thoughts on “Hardware: Picking a New CPU for Second Life

  1. Honestly… best to wait for AMD’s Zen in October.

    And it’s important because AMD hasn’t seriously tried to compete in CPU for gamers in a long while and they always offer at lower price than Intel’s. Now they are.

    It could be a flop… but it also could be great. Tech experts believes their CPU FX model with 8 cores and 16 threads are to be priced around $250-$350. Spec that was on par with Intel’s Broadwell-E, which is priced at $1,100 currently.

    But then you’d have to get a new motherboard for it, but there’s a good chance that price difference with Intel could pay it off for that new AMD motherboard.

    • Thanks for saying.

      AMD could choose to compete in gaming. That would be good. From what I am reading scientists in places like CERN are excited about Zen. But, I’m not hearing much about gaming.

      They are going to smaller size (14nm) and packing in more cores (32). Historically more cores has forced down clock speed. We’ll have to see if they can solve some problems and provide more fast cores.

  2. Second Life viewers require you to get the fastest CPU on a per core basis (and a dual core or better; but more than 4 cores, or “hyperthreading” won’t do any difference whatsoever).

    Why ?
    Because the SL viewers’ renderer (unlike almost all recent games) is a mono-threaded task running in the main loop of the program, and the latter will consume one full core long before any modern GPU (such as the NVIDIA GTX 970 or better) gets saturated: the bottleneck is at the CPU level (and even at the CPU core level).

    Some graphics drivers (such as NVIDIA’s proprietary one) can use multi-threading by themselves, even when their OpenGL functions are called from a single-threaded software: enabling multi-threading in one such driver will get you a 20-30% fps boost at the cost of the consumption of a third to one full core processing power (meaning the viewer will consume 1.3 to 2 full cores while rendering a fully rezzed scene).

    During rezzing, the viewer will also make use of threads to fetch, decode and cache the textures and meshes, and up to half a CPU core may be consumed while it happens (thus why a quad core will give you slightly better results than a dual core CPU).

    It means that the best processor for Second Life is a quad-core with the highest clock speed * IPC (instructions per clock) product. A Core-i5 with the best overclocking capability is for now the best choice (at least until AMD comes up with a Zen CPU that can compete with Intel on this front).
    My 2500K (Sandy Bridge Core-i5) gives wonderful results at its 4.6GHz overclock speed (and probably equivalent results to what a Skylake would provide, given the latter, while providing a somewhat better (~20%) IPC, got a somewhat lower (~20% as well) stable overclock speed).

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