My gaming computer is an old Alienware x51 r2. I've been slowly upgrading it (16 GB RAM, GTX 970 4 GB is on the way). I'm thinking about upgrading the CPU from a dual-core to a quad-core (i3-4130 to i7-4790). It seems like the i7-4790 is only slightly better at single-thread benchmarks. So I'm thinking, if sims only use one or two threads, it's probably not worth it. Does anyone know if I'd get a big boost by going to the quad-core CPU for my sims (DR2.0, AC, rF2, AMS, ACC)?
How many CPU cores do I need?
- Thread starter David Mann
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To partially answer my own question, just saw this thread:
www.racedepartment.com
Here are my takeaways from that thread:
~More cores are good for AI in ACC (AI split among cores)
~For AC, ACC, and R3E on a high-end machine, four cores is the sweet spot (not sure how that translates to my potato)
Test: CPU Core count and RAM scaling in ACC, AC1 and R3E
Hello guys Couldn't find decent data so I did these tests myself during the holidays. Max settings @ 720P (Max distances, Max shadows, Max mirrors etc) to push for the max cpu drawcalls. Heavy duty multiplayer race replays were used, with 20~30 cars. 1 entire lap per test. With the camera set...
www.racedepartment.com
Here are my takeaways from that thread:
~More cores are good for AI in ACC (AI split among cores)
~For AC, ACC, and R3E on a high-end machine, four cores is the sweet spot (not sure how that translates to my potato)
The faster the better ATM but it seems ACC likes more cores if you want more Ai but i have 4c 8t 7700k and its fine in ACC for 24 Ai and pretty high-epic settings at 5830x1080 .
R3E like single core but as fast as possible .
You will notice going to 8t mainly because there is now a bit of headroom for Windows to do its thing while your games do theirs .
There are people on here and other forums who will say differently and other who will agree . In the end more is always better , be it cores or frequency .Just get the most of either or both you can afford .
R3E like single core but as fast as possible .
You will notice going to 8t mainly because there is now a bit of headroom for Windows to do its thing while your games do theirs .
There are people on here and other forums who will say differently and other who will agree . In the end more is always better , be it cores or frequency .Just get the most of either or both you can afford .
Note that both the i3 4130 and the i7 4790 are hyperthreaded, so should really be considered a quad-core and an octa-core CPU, respectively.
As for upgrading from the i3 to that i7, while most sims won't really be able to take advantage of the added thread, you should still see some nice performance increase. From what you mentioned, AC, rF2 and AMS should probably give you at least 20% more performance. DR2 and ACC are somewhat better multithreaded, so the gain might be higher there (but...it's always complicated with multithreading).
Generally you will probably be limited by your GPU more at that point, depending on the game and your settings as well.
As for upgrading from the i3 to that i7, while most sims won't really be able to take advantage of the added thread, you should still see some nice performance increase. From what you mentioned, AC, rF2 and AMS should probably give you at least 20% more performance. DR2 and ACC are somewhat better multithreaded, so the gain might be higher there (but...it's always complicated with multithreading).
Generally you will probably be limited by your GPU more at that point, depending on the game and your settings as well.
That ACC CPU scaling test you linked has been told buy Kunos that it isnt a CPU test while using the replay ! The replay is a GPU and single core test and a live race is needed to test CPU scaling for ACC ! Not sure about the other titles though .To partially answer my own question, just saw this thread:
Test: CPU Core count and RAM scaling in ACC, AC1 and R3E
Hello guys Couldn't find decent data so I did these tests myself during the holidays. Max settings @ 720P (Max distances, Max shadows, Max mirrors etc) to push for the max cpu drawcalls. Heavy duty multiplayer race replays were used, with 20~30 cars. 1 entire lap per test. With the camera set...
Here are my takeaways from that thread:
~More cores are good for AI in ACC (AI split among cores)
~For AC, ACC, and R3E on a high-end machine, four cores is the sweet spot (not sure how that translates to my potato)
i7 4790 non-k has an all core boost of 3.8 GHz, so you will gain about 10% in single core (3.8 vs 3.4 GHz), plus maybe a few more % from the larger cache and under scenarios where not all cores are in use, where the 4790 can boost even higher. The deals on used 4th gen i7's aren't that great though, so I'd at least consider upgrading to Ryzen 3rd gen or i5/i7 9th gen system (note that the 10th gen upcoming Intel CPU's will again require a new socket, which is why this platform sucks to me).
The computer has a compact "bookshelf" style case, with a custom motherboard design to make that fit. So, I'm stuck with that motherboard and the CPUs that have been tested for it. I'm trying to squeeze several more years out of this computer before building a new one. The 4790 is the best CPU I can get. I may get the "K" version depending on how much power the computer uses (I just upgraded to the biggest A/C adapter, which is only 330 W).
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I would say 4 cores is more useful if you want to run multiple apps as well as the sim.
I don't think anyone has done any real world testing various CPU's running a sim at the same time as other apps commonly used in simracing? i.e. Crewchief, Teamspeak, Discord, Simhub with dashboard overlays.
In my experience these apps can all sap performance especially on systems with lower core counts.
Ideally you want to make sure the core that is doing the rendering (the one that is maxed out when the game is running) is not doing anything else.
Teamspeak especially on certain busy days can make RF2 choppy AF as it bumbles its way into the games rendering thread.
Saying that would have thought it would make more sense to wait and save up for a newer MB and CPU later on.
Number of cores used by the sim is determined by which API it uses and how optimised the developers have worked the code. DX12 titles are capable of scaling to high core counts and even able to split the rendering pipeline into multicore if the developer put the work in. But yeah most at the moment are on DX9 or DX11. Limited upto 4 cores. I think this is going to change however on newer sims that will use DX12 or Vulkan.
I don't think anyone has done any real world testing various CPU's running a sim at the same time as other apps commonly used in simracing? i.e. Crewchief, Teamspeak, Discord, Simhub with dashboard overlays.
In my experience these apps can all sap performance especially on systems with lower core counts.
Ideally you want to make sure the core that is doing the rendering (the one that is maxed out when the game is running) is not doing anything else.
Teamspeak especially on certain busy days can make RF2 choppy AF as it bumbles its way into the games rendering thread.
Saying that would have thought it would make more sense to wait and save up for a newer MB and CPU later on.
Number of cores used by the sim is determined by which API it uses and how optimised the developers have worked the code. DX12 titles are capable of scaling to high core counts and even able to split the rendering pipeline into multicore if the developer put the work in. But yeah most at the moment are on DX9 or DX11. Limited upto 4 cores. I think this is going to change however on newer sims that will use DX12 or Vulkan.
4 cores (or rather threads) is what I would consider the minimum nowadays. Most sims will utilize 2-3 threads at least (some of them more), leaving only one thread for the rest of the system and potential apps. The sweet spot would be 6 threads, 8 if you can afford it to have more free resources available for background stuff. Above that you won't see much difference.
All these apps have negligible impact on the CPU.
There is usually no such thing as "core that is doing the rendering" or "the one that is maxed out when the game is running", your OS and CPU should be actively spreading the load over available threads (what you call cores) to optimize performance. A single core being maxed out while other cores don't do much is basically a sign of things running sub-optimally, at least on current hardware. Ideally, you should be seeing activity on most threads (cores), regardless of how many threads the game itself is actually "using".
What do you mean "bumbles its way into the game's rendering thread"? Why would TS do that? Are you talking about some sort of TS add-on that shows you some kind of overlay?
Way too simplified, if not downright innacurate. I'm not entirely sure about DX9 and would have to dig up some information, but I'm pretty sure DX11 is not limited to 4 threads (or, again, as you say, cores). There are DX11 games that will use way more threads than that.
Yes as long as they are not trying to compete on a core which is being maxed out. Sometimes Windows scheduler gets this wrong and you have to manually tell some apps to not use a specific thread to take the load off the one that is maxed out.
That's not my experience with any game. If I refer to RF2 for reference which is running DX11, when its running on its own and I give it 8 threads to work with, it uses 1 thread a 98%, a 2nd at 80%, a 3rd at 20 %, a 4th at 10% a 5th at a 2-5% and a 6th at 2% the 7th and 8th are doing nothing. This is not spreading the load evenly over the threads. If the thread that is running at 98% has another process forced on it it will cause a conflict and then you will experience stuttering or frame drops etc. I believe all games that use DX11 do this, but how they are distributed over the threads demonstrates how well optimised the game code is written for DX11.
A core that is being used way more than another means the developer has not worked hard enough to split the code into parallel code over the cores. This is very difficult to do for some things, notably s397 stating that the tyre physics as being one example which is difficult to split up.
This was my point above about windows scheduler not allocating processes correctly sometimes. I'm not sure why this happens, maybe it's a preference on the cores being used. Like on my Intel 7700k system tasks always seemed to run on CPU 0 whether or not something else is maxing it out already. You have to tell other apps to run somewhere else to be sure there is no conflict.
Yes fair enough, DX11 is not limited to 4 cores. I don't know what its limit is to be fair, but it is limited in what it is able to split onto separate cores no matter how good the programming is. I think that is what I wanted to say.
DX11 is essentially just a tool / API for programmers to use.
Programmers create the code that runs on DX11, how optimised this code is for DX11 dictates how well DX11 can distribute it over several threads. If its very badly optimised DX11 will still dump most of it onto one thread.
WIndows scheduler is then supposed to take the load its given and send it to the best thread for the job as evenly as possible. But it's not fool proof at all in my experience.
Think I bit off more than I could chew here and over generalised, wish I new more about programming and how DX11 and DX12 work.
I'll do a Screenshot on Monday but I'm very sure my rF2 loads every CPU thread evenly.
All 8 threads/cores being used to the same, slightly fluctuating amount. And not more than 50%.
About the creator's question:
330w isn't much and you shouldn't forget the heat that a higher end CPU is generating either since you probably don't have space for a big fat cooler...
The problem with your pc is that putting a 4790 in it won't give you a massive performance boost in comparison to the price you'd pay.
How much would a 4790 be btw?
Also putting in an i3 but k version would probably give you the same boost.
3.4 GHz or the i7's 3.8 GHz aren't much. The 9th gen Intels basically all run at 5 GHz or even more!
I know a few guys who overclocked their 4790k to 4.7-4.9 GHz but that wouldn't be possible with your 330w..
Overall in my opinion, the i5 k version of your CPU gen would be the best... And then overclocked to what's possible with the psu and cooler...
To check the wattage also buy a little wattage meter and plug it between the pc and the wall socket to check how much headroom you have left.
Then do a stress test with furmark or msi kombustor on your gpu and at the same time use thr furmark or kombustor "CPU burner" or whatever it's called. There's a button for CPU...
Throw 4 threads at it and check the power drain.
It's not very accurate since your psu doesn't have 100% efficiency but you'll see a rough estimation.
Maybe do this before buying a cpu...
Another thing: is your i3 Mainboard even able to overclock a k version?
Which chipset do you have?
Overall, depending on overclocking abilities, cooler, the price for the 4th Gen CPUs for you...
Saving a bit and going for a 9600k(f), 16gb 2400 MHz ddr4 and a Gigabyte z390 elite, and of course a 30€ standard case + be quiet/Silverstone/quality psu of 500W would boost your cpu performance into the next stratosphere...
And not extremely expensive.
All 8 threads/cores being used to the same, slightly fluctuating amount. And not more than 50%.
About the creator's question:
330w isn't much and you shouldn't forget the heat that a higher end CPU is generating either since you probably don't have space for a big fat cooler...
The problem with your pc is that putting a 4790 in it won't give you a massive performance boost in comparison to the price you'd pay.
How much would a 4790 be btw?
Also putting in an i3 but k version would probably give you the same boost.
3.4 GHz or the i7's 3.8 GHz aren't much. The 9th gen Intels basically all run at 5 GHz or even more!
I know a few guys who overclocked their 4790k to 4.7-4.9 GHz but that wouldn't be possible with your 330w..
Overall in my opinion, the i5 k version of your CPU gen would be the best... And then overclocked to what's possible with the psu and cooler...
To check the wattage also buy a little wattage meter and plug it between the pc and the wall socket to check how much headroom you have left.
Then do a stress test with furmark or msi kombustor on your gpu and at the same time use thr furmark or kombustor "CPU burner" or whatever it's called. There's a button for CPU...
Throw 4 threads at it and check the power drain.
It's not very accurate since your psu doesn't have 100% efficiency but you'll see a rough estimation.
Maybe do this before buying a cpu...
Another thing: is your i3 Mainboard even able to overclock a k version?
Which chipset do you have?
Overall, depending on overclocking abilities, cooler, the price for the 4th Gen CPUs for you...
Saving a bit and going for a 9600k(f), 16gb 2400 MHz ddr4 and a Gigabyte z390 elite, and of course a 30€ standard case + be quiet/Silverstone/quality psu of 500W would boost your cpu performance into the next stratosphere...
And not extremely expensive.
How do i tell a game to use a specific thread or threads?
I only ever tried it with process lasso.
My performance became a lot worse but it was nice to see rF2 running on 3 cores with 90% core load
Method one: go to details under task manager right click the app and select cpu affinity. You can then select which thread.
This method however needs to be repeated each time the app is opened. But it can be used as a quick fix.
Method two: get process lassoo, you need to pay for a licence however. It does the same thing as task manager but remembers the settings.
For what it's worth...I just upgraded my old system as I was holding out as long as I could but it just struggled with all the new titles.
I5 3570k @ 4.5ghz with a gtx 970...the CPU ran at 100% in AC, ACC and pc2.
I found some deals and was able to upgrade to a i5 9600kf with msi budget board for $350 cad..$260 USD and was able to reuse everything from my old build.
Personally I'd save a $100-200 and wait for a deal and upgrade to something newer, cause you'll just be in the same situation in a yrs time upgrading to used i7 4790
Thanks for the detailed post and questions!
I hear what you're saying about building a new machine with the good parts I have. However, part of the fun for me is tinkering with parts and getting the most out of what I have. I'm very pleased by the participation in this thread. Let's see how much we can soup up this old beater...
As part of my GPU upgrade, I went from 180 W to 330 W adapter. The extra 150 W may all go to the GPU, I'll need to see how that goes...
They're about $100 on eBay. That's really why I asked the original question. It seems like going from two cores to four would be worth it to me if we can make it work.
Yes, I'm going to test before and after the new GPU install, with stress tests and while racing, to see how much power I have left for a new CPU.
The chipset is either H87 or Z87. I'm on vacation so I can't check. I'm not planning on overclocking because of power and heat limitations. The thermal management in the case is pretty good, but I don't want to push it, especially with the extra heat from the GPU.
I hear what you're saying about building a new machine with the good parts I have. However, part of the fun for me is tinkering with parts and getting the most out of what I have. I'm very pleased by the participation in this thread. Let's see how much we can soup up this old beater...
I hear you, but I'm comfortable being several years behind the times. I think my standards are lower than most people's. I've been playing all the games I mentioned in the first post. It was really DR2 that pushed me to these upgrades, along with getting an ultrawide monitor with more pixels to push (2560x1080 vs. 1920x1080).
