Question Which cheap (perhaps used) old CPU should I get?

[DynV]

I'm going to be upgrading to a 3 years old computer. I've asked what was necessary for some gaming (Fallout 4) and from the list of GPUs I was given I found one is special that I decided to get in case one day I upgrade the rest of the computer. At the same time it was mentioned the CPU could be better. Since I've spend like 50% more on the GPU than the money I intended, I'll either keep the CPU or try to find a used one or one in--super--special that could be better for gaming. My budget is 50 CAD (as I'm writing this = 38.00 USD = 34.09 EUR), a reminder used is a possibility. I would appreciate an ordered list of the suggestions if you have > 1 (ie: aaa < bbb < ccc) The following is the parts I'll most likely have, the GPU is ordered not pre-paid so could be canceled but I doubt it:

• GIGABYTE GA-B150M-DS3H (rev. 1.0) LGA 1151 Intel B150 HDMI SATA 6Gb/s USB 3.0 Micro ATX Intel Motherboard
• Intel Core i3-6100 3M 3.7 GHz LGA 1151 BX80662I36100 Desktop Processor
• GeIL EVO POTENZA 16GB (2 x 8GB) 288-Pin DDR4 SDRAM DDR4 3000 (PC4 24000) Desktop Memory Model GPR416GB3000C15ADC
• ordered (not guaranteed of getting) GIGABYTE Radeon RX 590 GAMING 8GB REV2.0 1560 MHz Boost, 8000 MHz Memory PCI-E 3.0, DVI-D, HDMI 2.0, 3x DP 1.4 GV-RX590GAMING-8GD REV2.0
• Corsair CX Series CX450M 450W ATX 12V 80 Plus Bronze Certified SEMI-MODULAR Power Supply Unit
• Crucial MX300 M.2 2280 275GB TLC Internal Solid State Drive (SSD) CT275MX300SSD4

Thank you kindly

 

[MrN1ce9uy]

The i3-6100 is worth more than $35 USD (currently $72 USD on eBay). Just use it until you can upgrade to something better.

 

[cryoburner]

Yeah, that 2-core, 4-thread i3 isn't going to be ideal for demanding games, but it might still be reasonable enough to get fair performance in most titles. I don't think you're going to find a better CPU within that price range.

What sort of graphics card were you using before?

 

[DynV]

Is there a way to find out when the CPU becomes the bottleneck, and what portion of slowdowns it create? If I can detect it becomes my main bottleneck, I'll find a way to get some money, even if in a few months; and likely the CPU would be used.

I'm to upgrade to that old PC, I'm on an older one ATM, and there was no GPU coming with that upgrade.

 

[MrN1ce9uy]

Install MSI Afterburner w/ RivaTuner and enable the On-Screen Display (OSD) to show the CPU usage and GPU usage and framerate. When the CPU usage is 98-100% while the GPU usage is below 98-100% then that is a CPU limitation (aka bottleneck). Watch your framerate also to see the loss in performance.

 

[InvalidError]

When the CPU usage is 98-100% while the GPU usage is below 98-100% then that is a CPU limitation (aka bottleneck).

You can have a CPU bottleneck LONG before getting anywhere near 100% CPU usage: as soon as a performance-critical thread hits 100% activity, you have a CPU bottleneck. On a quad-core CPU, you could see a bottleneck as soon as 25-30% CPU usage in the case of a mostly single-thread game or 50-60% for a lightly threaded game like WoW.

 

[DynV]

Is there a logged version of such software? That I could get something like: How long was there bottleneck (of CPU & GPU), the average length of each, etc. I'd prefer not having to keep an eye on the OSD during the moments where such bottlenecks really mattered (ie: combat in Fallout 4).

 

[TJ Hooker]

Is there a logged version of such software? That I could get something like: How long was there bottleneck (of CPU & GPU), the average length of each, etc. I'd prefer not having to keep an eye on the OSD during the moments where such bottlenecks really mattered (ie: combat in Fallout 4).

You could use hwinfo, which has an option to log results to a csv, although I'm not sure how useful that sort of detailed information will really be.

As an aside, you want to look at max utilization of any individual thread/core, not overall usage. If even one core is maxed out you'll have a bottleneck.

 

[InvalidError]

If even one core is maxed out you'll have a bottleneck.

Depends on what that core is "maxed out" on. If all the thread is doing is busy-waiting on a soft-lock (repeatedly polling a memory location for a flag), it can have 100% load doing little to no useful work. It is a horribly inefficient use of CPU time but busy-waiting like this is common in software when you don't want to incur the 1-2µs overhead associated with using system objects (semaphores and mutexes) along with possibly losing the remainder of your current time slice if the OS decides to schedule something else on your core or put the core to sleep instead of letting the thread waste CPU time and power on a lock.

 

[cryoburner]

You could probably just check whether the graphics card utilization drops when your frame rate drops, while largely ignoring the CPU utilization. If the graphics card utilization drops substantially during low-framerate situations, then the game is probably waiting on the CPU to complete its work. If the graphics card is near 100% utilization though, then the CPU is likely performing well enough to keep up with the card. Of course, that will vary from one game to the next, and is probably only worth looking at if you are noticing performance issues in a game.