The importance of Cache Freq Overclock in p3d

[Alessandrov81 2]

Greetings,

 

with my old AMD X4 955 i had noted the importance of increasing the frequency of the Northbridge while significantly overclocking the CPU Freq.

Switching to the new I7 4790K I had understood that the most widespread opinion is that it is sufficient/reccomended to increase the multiplier and voltage to get a good overclock. I was not entirely convinced, given my previous experience, but I thought the new processors were simply different...

 

I came to doubt that though, after reading some thread on Tom's hardware forum (i.e. http://www.tomshardware.co.uk/answers/id-2475409/overclocking-cpu-cache.html), infact i believe, that since overclocking cache does not really matter for gaming, the importance of cache Freq. for simulators as P3D, for which the memory bandwidth is very important, is actually underrated (at least I have not read a lot of discussion about it on the forums of P3D or FSX).

 

I'm not saying Northbridge and cache are the same, actually i know they are a lot different CPU, but both NB and cache have impact on memory bandwidth that is the point.

 

Accordingly, yesterday I changed my BIOS settings (in which I had only changed the frequency of the CPU core 4.7GHZ and its voltage to 1.25V) and I increased the frequency of the CPU cache from AUTO (3,9GHZ) to 4,6GHZ and its voltage from AUTO (around 1,1 i think) to 1,26V. I tried 5-6 Orbx airports and I seem to notice an increase of at least 5 FPS, although the increase is not linear in all areas (for example, in Seattle does not seem to see it, maybe there are other bottlenecks).

 

Infact, now I can get 30-31 FPS (which is max since i had it locked) much almost stable at all airports / areas Orbx exception of metropolies (Seattle...). While before i was getting usually around 25-26FPS. Unfortunately I have not had the chance to test it more (in particular with FPS unlimited).

 

So, what am i asking?

 

1) If you overclocked CPU freq. but not the CPU CACHE freq. could you try raising Cache multiplier bringing it closer to that of the CPU (should fit a voltage slightly higher than the CPU core voltage) and test the difference in P£D performance?

 

2)  if you have already increased the frequency of the cache, can you tell me if you share the same improvement that I seem to see?

 

I would also be interested to know if you overclock the frequency of RAM and received any benefit, because after I tried to increase the frequency of my RAM from 1600MHz to 1866MHz but I do not seem to see improvements in FPS (perhaps just its stability?) Do modifing latency give better results?

 

tks!

[Michael Moe 495]

Hi ,

 

I have read the same but never tested it though because i thought the temp must rise as well. I have mine @4770K,4,6 with multiplier at 46x100 and 1.25V.

 

I will report back to see if i can raise it.

 

I actually lowered my RAM to 1333mhz from 1600MHZ but again cant remember why :unsure:

 

 

Btw. A-Mask Cores re-checking them for P3D.EXE via windowsTaskmanager reduces Temp 5-8c on Core 0 and gives me a fps as a bonus

 

Michael Moe

[Michael Moe 495]

Okay

 

Test shows absolut no difference on my system regarding FPS with cache at 4.6 GHZ vs 3.9GHZ

 

Michael Moe

[Alessandrov81 2]

Hi Michael,

 

I am not surprised anymore about the performance's differences of the various tweaks on different systems since i tried OP = 1, that practically changed everyone's life and it gave me negative results....

 

I'm using V2.4 don't know if it matters maybe no... Could it be the RAM downclocking which inhibits the improvement of memory bandwidth?

 

Curiosity: why are using taskmanager instead of AM? Did you find changing affinity in task manager is different than setting Affinity Mask in CFG? How many and which cores do you enable for P3d?

 

tks

[Michael Moe 495]

Hi Michael,

 

I am not surprised anymore about the performance's differences of the various tweaks on different systems since i tried OP = 1, that practically changed everyone's life and it gave me negative results....

 

I'm using V2.4 don't know if it matters maybe no... Could it be the RAM downclocking which inhibits the improvement of memory bandwidth?

 

Curiosity: why are using taskmanager instead of AM? Did you find changing affinity in task manager is different than setting Affinity Mask in CFG? How many and which cores do you enable for P3d?

 

 

I only use 4 cores but switching back and forth via taskmanager seems to offload something on core 0.It gain fps and heat on that core doing so.

 

Michael Moe

 

tks

[Alessandrov81 2]

I tried again cache at 3.9ghz and at 4.6ghz, in CYSE Swanson (Orbx payaware) i get 3-4 FPS more with FPS unlimited (37 vs 41)

 

the interesting thing is that if i add overcast and rain the difference is the same (33 vs 37)

 

nothing scientific but for now i'm keeping it

 

instead i returned RAM to stock setting because OC to 1866 keeping the same timings (9-9-9-24) was unstable also with 1.6volt. the difference how ever seems to be null for RAM ocing...

[Alessandrov81 2]

I noticed a strange thing: with cache @4.6ghz i was getting blurries after some minutes (LO cannot keep up i noticed that only today) - ceteris nothing else changed. So i tried to remove my affinity mask setting (AM=254) and the blurries were gone + i decreased FFTF from 0,11 to 0,01 so i get rid of some micro stutters and increased FPS more.

 

Is it possibile that a different cache frequency may change my cores behavior and so my optimal affinity mask setting?

 

The only thing i now is current settings give the best simming for me up to today.