Overclocking CPU Cache?

[TechyInAZ]

Some things I would like to know:

1. Is cache overclocking necessary?
2. Does it bring any speed improvements
3. How much voltage should the maximum be for cache?

I have a i5 4690K with the cache at 39x.

Thx.

 

[1LiquidPC]

It seems to benefit from memory related benchmarks and possibly software that heavily relies on memory bandwidth, though the actual speed increase is probably slim. In games, it makes pretty much zero difference. I can't say for sure it's "necessary", but I've read ideally you'd want your cache speed to be within 500mhz or so of your CPU clockspeed. I've read voltage should be ok under 1.3v

 

[yumri]

that is even possiable?

 

[airplanegeek]

1. It is not necessary
2. It will bring small improvements if your cpu speed is higher than around 4.4
3. http://www.tomshardware.com/forum/id-1722630/intel-god-quick-dirty-guide-4ghz-haswell.html

 

[TechyInAZ]

Ok. For now I have an overclocked i5 4690K at 4.5ghz. So should I bump it up to 4.2?

 

[yumri]

fro mwhat i have read you should try to put it also at 4.5GHz if at all possiable of course

 

[airplanegeek]

4.2 will suffice, as long as the different isn't too big between cache and cpu. there is no reason to try and reach 4.5 if you chip doesn't like it

 

[yumri]

overclocking CPU cache espcially L1 cache is already going to do almost nothing so why not go for the best that you can tweak it too?
But yes i do agree that if 4.2 is stable but 4.201 and higher is not then stay at 4.2 as you want it to be stable more than anything else.

 

[TechyInAZ]

Ok ill shoot for 4.2 then. The goal of my overclock is to get as much power savings as I can.

So how would I go about overclocking it? try bumping it up to 4.2 then leaving the cache voltage at auto?

And a little off topic, how many hrs should I run prime95?

 

[yumri]

i ussualy see reveiwers of overclocked CPUs usering prime95 for a straight 24 hours to make sure it is stable

 

[TechyInAZ]

i ussualy see reveiwers of overclocked CPUs usering prime95 for a straight 24 hours to make sure it is stable

I don't think I need to stress test that long. Some say only 4-6 hrs is good.

Plus, I use my computer for work too.

 

[yumri]

I kinda do not actually ussualy overclock on a work machine just on raspberry pis and the super cheap AMD based servers that i have built to which i can do it for that long to make sure that the overclock or underclock which ever is needed works properly without to much heat being generated by it.

 

[airplanegeek]

Never leave voltage at auto, you should know this. Only use the lastest version of Prime95 as previous versions are giving unrealistic heat output. 4-8h should be plenty of buffer. Then fire up a game or something for a while.

 

[TechyInAZ]

Never leave voltage at auto, you should know this. Only use the lastest version of Prime95 as previous versions are giving unrealistic heat output. 4-8h should be plenty of buffer. Then fire up a game or something for a while.

Yeah du.

I still have a few questions. Does your system HAVE to be Stable with prime95 on the heaviest setting?? Because I get BSODs if I put prime95 on the most extreme stress test, but if I do a lighter stress test it doesn't bsod.

And how would I go overclocking the cache? is it the same as overclocking?

Sorry for all the questions, I can't find a lot on cache overlooking on Google.

 

[airplanegeek]

Prime95 isn't a really great stability test anymore, much more people are recommending aida64. Cache overclocking is same as cpu overclocking. Increase the cache/ring bus multiplier and then add voltage.

 

[TechyInAZ]

Ok got it, and speaking of prime95 I did some research and found out that prime95 is a bad tester for haswell. So I just switched to OCCT and am 45min into a stress test on medium data set (what's the difference between medium and heavy?).

Ill get into uncore overclocking tomorrow, so should I start at a baseline of 1.2v on the cache at 42 and work my way down?

For now I have a stable 4.5Ghz at 1.23vcore on the CPU.

 

[airplanegeek]

Yep, sounds good

 

[TechyInAZ]

One more small question, overclocking the cache also bring a BSOD if not enough voltage is applied right?

I'm asking this because on my older Pentium D overclock, my computer would act very weird sometimes if I put a certain vcore in compared to another.

 

[airplanegeek]

Yep, you need to ensure cache is also stable.

 

[TechyInAZ]

Just want to make sure one more time (just to be safe lol). It WILL BSOD if the cache voltage is insufficient right?

Just getting some weird behavior. When i have the cache voltage at 1.205 at 42 windows move around just fine while running the stress tester simultaneously, while at 1.180 at 42 i get 1-2 sec lags when moving a window with stress tester on too.

Nevermind, it's only happening on my CoreTemp window. My CPU-Z window and Thunderbird window move just fine.