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Low FPS on PC without full use of CPU & RAM

Posted: Tue Oct 11, 2022 2:31 am
by MisiakDP
Hey,
I have a large map and have only 30 FPS / 30 UPS on this computer:
- CPU: Intel i5-4590 3.30GHz, 6MB, cores: 4, threads: 4 (each core in use about 60% (not 100%)),
- GPU: PowerColor Radeon RX 6600 Fighter 8GB GDDR6,
- MOTHERBOARD: ASUS Z87-C, Socket 1150, chipset: Intel Z87, DDR3
- RAM: Kingston 8GB DDR3 1333MHz CL9

But I have 60 FPS / 70 UPS on other computer with this same save game (this same map):
- CPU: Intel i3-12100F 3.30GHz, 12MB, cores: 4, threads: 8,
- GPU: PowerColor Radeon RX 6600 Fighter 8GB GDDR6,
- MOTHERBOARD: Gigabyte B660 DS3H, Socket 1700, chipset: Intel B660, DDR4
- RAM: G.SKILL 16GB (2x8GB) DDR4 3200MHz CL16

CPU and RAM usage on old PC:
pics
So where is the problem? Why do I have such a low FPS/UPS on an older computer? Which component should I change for a better one to improve the quality of the game?

Re: Low FPS on PC without full use of CPU & RAM

Posted: Tue Oct 11, 2022 4:39 am
by vjbone

Re: Low FPS on PC without full use of CPU & RAM

Posted: Tue Oct 11, 2022 4:42 am
by MisiakDP
But why if my CPU is not used 100%? And RAM too.
How it needs the resources of PC?

Re: Low FPS on PC without full use of CPU & RAM

Posted: Tue Oct 11, 2022 4:56 am
by SoShootMe
MisiakDP wrote: Tue Oct 11, 2022 2:31 am Why do I have such a low FPS/UPS on an older computer?
In terms of Factorio performance, I think the most relevant differences between the two systems are:
  • 6MB vs 12MB CPU cache
  • DDR3 vs DDR4 RAM
  • 3.7GHz vs 4.3GHz CPU Turbo Boost
As with most games, it is normal for Factorio to be unable to fully utilise a multi-core CPU. This means Turbo Boost is often quite relevant, although given the CPU usage on the older system I doubt there is much use of it in that case.

The CPU and motherboard chipset are nearly eight years older in the older system. That's a long time, even if the rate of performance increase has slowed in recent years.

Re: Low FPS on PC without full use of CPU & RAM

Posted: Tue Oct 11, 2022 5:56 pm
by Rseding91
MisiakDP wrote: Tue Oct 11, 2022 4:42 am But why if my CPU is not used 100%? And RAM too.
How it needs the resources of PC?
CPUs have many cores. It's often impossible or impractical to try to use them all.

Imagine you have 4 cars (4 cores). You are trying to drive somewhere as fast as you can. The fact you have 4 cars doesn't help getting you to where you want to go faster. A faster car will help you get there faster. Now, if you have 4 people and only 1 car more cars can help. But you don't always have 4 people needing to go to multiple places at once.

Re: Low FPS on PC without full use of CPU & RAM

Posted: Fri Oct 14, 2022 4:13 pm
by quyxkh
Factorio becomes memory-bandwidthlatency limited as the map grows. Your haswell cores are starved waiting for data to arrive over the 100%-utilized main memory bus, because it's trying to do the same work with much smaller caches and much slower main memory.

edit: whoops. "I knew that." duh.

Re: Low FPS on PC without full use of CPU & RAM

Posted: Fri Oct 14, 2022 4:55 pm
by Loewchen
quyxkh wrote: Fri Oct 14, 2022 4:13 pm Factorio becomes memory-bandwidth limited as the map grows.
Latency not throughput. If you double the memory throughput but keep its latency you will see almost no performance improvement.