Is it necessary to run Prime95 for 24 hours?

[K-Hype]

I have heard countless times that you must run prime95 for 24 hours in order to determine if your overclock is stable. But do you really need to do that I mean I got more things to do on my computer than to run prime95 all day. I have overclocked my CPU to 4.5 GHz and I ran Prime95 for 6 hours I think that is enough right? What do you guys think? Should I run it for another 2 hours or is that good enough?
My specs:
Intel Core i5 4690K
Gigabyte Z97MX G1 Gaming 5
EVGA 16GB DDR3 2400MHz
Kingston HyperX 3K 120GB SSD
Western Digital Caviar Black 1TB
Seagate Barracuda 320GB
EVGA GTX 970 SSC ACX 4GB
NZXT Source 210 Chassis
Corsair CX600 Power Supply
Windows 7 Professional 64 bit

 

[migronesien]

Sure that's enough. I don't even run Prime after OCing at all. I just try normal gaming (something CPU heavy like GTAV) and if it doesn't crash it's fine.
Prime exceeds the normal amount of CPU usage anyway by a good bit. So if you don't had any trouble with 6 hours prime then you're 100% good.

 

[sportsfanboy]

i think that's more than enough. I personally will run a test like cinebench for a few runs. then if it passes that a few loops of x264. if all goes well after that i'll run prime and occt for about an hour or two a piece.

total testing time under 6 hours. all you really need to do after the tests have finished successfully is to play your games or encode, or what ever you use your computer for normally. if you happen to get a crash, go look at the dump file and you can give it a tweak as needed. seems like the best method to me. I mean... i have tested for hours before, then fired up BF4 and crashed in a half hour of playing.

 

[K-Hype]

Cool nice to hear that, I was expecting some answer saying "yes you must run prime95 for 24 hours" I will probably play Crysis 3 for a little while since that game is pretty CPU intensive as well.

 

[sportsfanboy]

there's other factors as well. if you overclocked your cache or memory. but if you did your homework, you should be able to sort out any instability quite easily once you have a good feel for your system and the settings in bios.

Yeah, i believe the need for overnight or even longer prime runs, became unnecessary after intels first gen "i" series chips

 

[Redneck5439]

Cool nice to hear that, I was expecting some answer saying "yes you must run prime95 for 24 hours" I will probably play Crysis 3 for a little while since that game is pretty CPU intensive as well.

Most extreme overclockers will tell you unless it passes Prime 95 for 24 hours it isn't truly stable. At the core of that debate tough is the fact that noting is going to pound your CPU as hard as Prime 95. Prime 95 should be run as just running games to test it (even CPU intensive ones) doesn't mean your stable. You may game just fine, but when you go to do something more such as intense video editing, encoding, ect... you may end up with a BSOD or restart because your really not stable. As to your question, yes if you passed 6hrs of Prime 95 your stable. When I overclock a computer for a customer I will usually call it good to go if it passes 4hrs of Prime 95 as nothing is going to pound the CPU harder than that and most people aren't video editing all day long every day (of course if someone was I would run Prime 95 for 24hrs to ensure stability for that heavy torture).

The vast majority of the time if you have a problem it will show within the first 30 min of running Prime. While testing my own rig I called it good after 4hrs of Prime 95 but later when I was going to be out the vast majority of the next day I started it in the evening and let it run for 24hrs to make sure my cooling could handle the huge load and everything was 100%.

 

[sportsfanboy]

most of the extreme overclockers over at overclock.net don't do prime for 24 hours anymore. In fact, most of them don't even use prime now a days.

X264 and occt are better than prime95 imo

 

[Tradesman1]

Yeah, Prime has sort of passed it Prime (pun intended 😉 ), many of us just run a variety of things (ROG RealBench, LinX, OCCT). Plus just running the rig can give a good indication, I seldom ever run Prime and when I do maybe 20-30 minutes

 

[K-Hype]

Yes, I overclocked the Uncore ration to 1:1 with the Core clock and its been running fine. I started out just overclocking the Core Clock to 4.5GHz then ran Prime95 for 6 hours then went back to the bios and overclocked the Uncore to 4.5GHz. I ran Prime95 for another 6 hours and it was fine no errors or blue screens. My ram is at stock speeds I just enabled XMP so it can run at 2400MHz instead of 1333MHz. Back then I don't even use Prime95 to overclock my Core 2 Duo E6600 and it was stable in games.

 

[K-Hype]

I don't know man but it's truly hard to determine whether your system is fully stable. Lets say you ran Prime95 for 24 hours and you stop it afterwards. But what if it blues screens at the 25th hour but you'll never know because you stopped the stress test after 24 hours. What if it fails after 48 hours, what I'm saying is that it is rather difficult to say "your system is fully stable" because it may blue screen crash after 72 hours. But realistically nothing can stress your system that hard. Even though I can the Prime95 for over 6 hours but I can't say my system is truly 100% stable because it may blue screen after 72 hours non stop. But no one has the time for that.

 

[K-Hype]

I'm not so sure about X264 but OCCT isn't as stressful as Prime95. I tried 4.6GHz and ran OCCT and it was fine for 2 hours, after that I decided to fire up Prime95 and it blue screen in like 15 minutes.

 

[sportsfanboy]

Was that prime that uses avx i struction set. Be cause that version is not good for haswell and above.

 

[K-Hype]

Damn my computer blue screened with the Uncore at 1:1 ratio after another hour of Prime95 but can go on if Uncore at default speed 3.5GHz. I have my voltage at 1.250V I was wondering what the max safe voltage the i5 4690K can take. I increased my voltage to 1.275V but I haven't had the time to test Prime95 yet probably try it again either tomorrow or Tuesday.

 

[sportsfanboy]

what does hwinfo say the vcore is at full load? generally 1.3 is considered safe with good cooling. i run my 4790k at 1.32 full load, but i have very good air cooling.

You don't have to run 1:1 cache... i would try backing it off until you're happy and stable with the main overclock. then if you must over clock the cache, you can try adding voltage to it, and other values like system agent and io voltages. also i see you're running 2400 ram, that is already starting to push the upper limits of the chips IMC.

higher cache speed doesn't really add any tangible real world gains except maybe some niche programs, that are incrediblely ram intensive. other than that, you're really looking at synthetic bench mark gains.

I'm running 4.9 ghz core and 4.2 ghz cache for my daily overclock. core is king... youre much better off with higher core and stock cache, over the ladder.

 

[K-Hype]

Wow you must have a really good chip. I left my computer on in the morning running Prime95 with my CPU core at 4.5GHz and my Uncore at 4.0GHz before going to school. I just came back and its still running it went past 7 hours now. I guess it seems stable enough for me. I might actually overclock the Uncore a little bit higher to maybe like 4.3GHz and test that out tomorrow. I also tried Crysis 3 the other day and I played it for about 2 hours straight and it was running great on the second level which was the most CPU Intensive part of the game. What is funny is that I can't seem to get my CPU to 4.6GHz it always BSOD at any voltages even at 1.305V. I tried disabling XMP with my ram at 1333MHz but it still wasn't stabled. At 4.7GHz it won't boot into Windows 7 at any voltage, it probably needs like 1.450V but I'm not going to do that since I only have a Cooler Master Hyper 212 Evo. I might upgrade to a Corsair H100i GTX liquid cooler a little before Christmas and try to hit 4.6GHz with voltages a little bit higher. I am just addicted to overclocking.

 

[sportsfanboy]

what's you're input voltage set to?

I have a pretty good chip, but the i7's clock higher than the i5's as a rule. i good majority of the 4790's can do 4.7 without too much trouble.

 

[K-Hype]

If you mean core voltage right now I have it at 1.250V. I plan on trying to get overclock at bit more once I get a Liquid cooler so I can over volt a bit higher without the temperatures hitting to the mid 80s

 

[sportsfanboy]

no i mean input voltage... It might be called something different on your board. but it should be set roughly .6v higher than vcore.

if that value is too low, you can throw a ton of voltage to the cpu and it won't matter.

 

[K-Hype]

If you mean the CPU VRIN then it is on auto next to it says 1.800V. Should I increase it or should I just leave it as it is. I don't know much about the CPU VRIN

 

[sportsfanboy]

I would soot for .6 above vcore, its more than safe. In some cases, using the correct input voltage can allow for lower stable vcore. But the rule of thumb is .6 higher, more is some times needed with higher over clocks.

 

[K-Hype]

So I should increase the VRIN to 1.850V and then up the Core Clock to 4.6GHz. But would increasing the VRIN voltage increase heat output?

 

[sportsfanboy]

Not really more heat, maybe a very small amount in the little bit you're talking about. i would keep it .6 above vcore vrin is the voltage that feeds the voltage regulation within the chip. if it's too low, you will struggle getting steady voltage loads because of the nature of electricity. So vrin basically affects vdroop/load line calibration.

this value is safe to 2.0 or more so i wouldn't worry about it.

You can try 4.6, but i'm not sure just changing vrin voltage will do it. i suspect youre 2400 ram and the cache ratio youre running, are holding your core overclock back.

Personally, i would leave cache at stock, down clock the ram to 1333, and then go for the best core over clock you can get. after that, go back and get your ram stable at 2400, and cache last.

 

[K-Hype]

I tried lowering the ram back to 1333MHz as well as the Uncore back to 3.5GHz but 4.6GHz was still a no go it BSOD after 20 minutes so I'm going to try upping the VRIN and up the Vcore a bit to see if it will make 4.6GHz stable. I may have gotten a chip that is a below average overclocker.

 

[sportsfanboy]

Yeah sometimes you need more vcore, just increase the vrin voltage to match as you go. Keep an eye on temperatures also if haven't already.

 

[K-Hype]

Yeah usually temps are in the mid 60s to lower 70s the max I've seen was 75 degrees Celsius in Prime95. I will probably keep upping the voltage till temps hits the lower 80s then I will stop. Honestly I probably don't even need a CPU overclock but its just once I start overclocking I can never stop.