Solved Can a CPU be completely unable to be overclocked?

So, I am a complete overclocking newbie. Read up around a bit and gathered the courage to try it out. I even found and followed to the letter a guide for overclocking the exact same motherboard and CPU combo I'm using (http://www.tomshardware.com/forum/263043-29-1156-core-core-overclocking-guide).

To start out, i tried out what they say on the guide should be a very easy and safe overclock of 3.6 GHz. Sadly following that guide failed miserably, my PC wouldn't even start BIOS afterwards, it would just stay powered on for a few seconds, then shut down again.

After resetting the CMOS, I tried doing the exact same thing again, except only doing a tiny 20x 150 overclock, with the same settings, and voltages of the higher overclock. Same thing happened again. I even tried doing the light overclock at the maximum voltages stated in the guide, same problem.

Is there something extremely obvious I'm missing, or is my CPU sort of unable of being overclocked because it has a few years under it's belt already?

Also, my PSU isn't exactly as powerful as recommended for my system, but from what I was told, it is of a higher quality than most brands, and thus it can get away with being a bit weaker (don't understand the logic behind that, but indeed it never failed me all these years). Could that be what's causing my overclocks to fail? No power to spare from the PSU?

PC specs are:
Gygabyte P55A-UD5 Motherboard
i5 750 @ 2.67 GHz (4 CPUs)
2x4 GB DDR 3 RAM sticks, 1600 frequency, timing 9 9 9 24

If PSU specs are relevant, let me know what info you need, and I can look it up on the sticker.

Thanks in advance for any help!

 

DxDiag says: Award Modular BIOS v6.00PG

All BIOS update downloads on Gygabyte's website list their versions as F5 up to F13b so I'm not sure what version exactly I should download. Never updated it before, kind of hesitant to.

I appreciate the help, but could you please explain why you think that's relevant? Not that I doubt it, it's just for future reference if I decide to overclock other machines in the future.

 

I think my cooler/heatsink might be the culprit here. Is it possible that the temperature is rising quickly during bootup after overclock attempts, causing them to fail?

I'm using the stock cooler, which keeps on gathering soot surprisingly quickly. The CPU when idling is running at ~60º C which seems very high. Under stress it goes up to almost 100ºC. Hopefully the CPU isn't damaged.

I can't know for sure if the heatsink is seated properly, since I have to take it out every few months to clean the soot out, and the little plastic connectors are such a pain to re-install, especially vertically, that they got a bit damaged over the years. I also haven't been using proper thermal paste for over a year.

I'm going to buy a Hyper Tx3 Evo Cooler Master to slap on it instead. Hopefully it doesn't gather soot and require cleaning as often as the stock cooler.

 

You need prefilters,any foam that's breathable will do the job (should be able to see through the foam or see daylight) where your intake grills are.Elevate the computer a few inches off the ground as well may help some.If it has to be on a floor place some matting preferably a nice thick pile like carpet as it will act as a dust trap,however the filtering will do the job fine,it works great on mine

thermal paste is used as the medium for heat transfer from cpu to heat sink,get that wrong would be like running a car with too low water level,at idle it'll be fine,give it load the temp will sky rocket,will be worse in summertime

 

Yeah, the tower is sitting on my desk next to my monitor, but it still gathers soot and dust like crazy. I'm using an old Cooler Master HAF case, which has mostly grating and lots of fans all over, so it would require way too much foaming, and might actually end up blocking the airflow.

As for thermal paste: funnily enough, I had been using baby rash cream instead of it (composition is actually surprisingly close to that of thermal paste, but obviously not optimal for this job) as I had run out of thermal paste last year which was last time I had to clean the cooler and was admittedly too lazy and in too much of a rush to get the computer working again, to go buy new thermal paste. It was supposed to be just a temporary placeholder thing until I did get some thermal paste, but funnily enough, my temperatures on the first few months were actually lower than when I was using proper thermal paste, so I eventually ended up just leaving it like that and didn't have any other high CPU temperature signs ever since up until now.

I am also fairly sure the high temperature I'm experiencing right now is more to blame on the silly plastic push pins the stock i5 cooler has, that get damaged really easy after being removed a couple of times for cleaning and thus I'm fairly sure it's not seating properly on the CPU anymore, which is causing my problems. Unfortunately I didn't know the T4 cooler from cooler master has metal push pins instead that are a lot sturdier, before I ordered the T3x which also has plastic pins. Oh well, live and learn, I'm hoping the new cooler will last for a couple years, at least, until I have to buy a new CPU and motherboard.

 

The only fan vents that require covering is the in flow on the case,there's no issue for air flow while using a filter in front of the inlet fans ,i've seen a few of the oem manufacturers have pre-filters in place on the inwards flow,i'm surprised yours already doesn't.I use automotive 10mm foam.The pre filters i've seen on oem's is quite thin at around 3mm & attached to a grated gauze like thing very similar to a k&n air filter for a vehicle.Next time your in a computer shop see if they have any,when blown through there's no resistance as the holes in the foam are quite large

 

Ah, I see. Yeah that sounds like a neat solution, but does that foam also prevent dust buildup in the heatsink itself, or only in the fan? Because the majority of it ends up stuffing the space between the heatsink's metal sheets (or whatever they're called).

 

This particular computer dell optiplex 755 only has one large draw through (inlet) fan at the front below the floppy bay ,the fan is about 3" inches or more away (faces front to back of comp case) & is half the size of the grill at the front.The heat sink is massive i don't know why a fans needed..lol...(the heat sink fins unlike my hp below sits parallel with the case not vertical) There's one exhaust fan which is at the top rear inside the psu,below that is another grill for more outlet pressure.Every six months i give the foam a dust off (it sits directly behind the front panel grill & covers all of it).As for the cooling fin dust you ask about,i say what dust ? (there are specs of dust here & there & nothing like what i "KNOW" you are talking about that actually blocks anything,there is none of that build up,most of it is usually in the base of the case & quite fine.There is a very small amount of wispy type dust on the tips of the graphics card fan,nothing blocking the fins that i recall & it had been in the case around a year or more before i had to remove it due to fan bearings

The hp presario S5020AN i have & was the original comp i started covering holes & was a bugger for getting blocked fans & fins including graphics card.The foam pretty much stopped that bs.the gaping holes were two full front to back strips along the lower side inspection panel & the lower half of the front panel,however there was a lot of draw through from the flopppy & every dam gap (dust was always getting trapped between the dvd drives etc & being sucked inside the floppy)

summary:
It worked wonders for me,so much so i did the same to a mates comp & my dad's,now that i think about his foam will be due for a dust off

 

Well, my new cooler just arrived and I installed it. It's a bit noisier than the stock one, but the CPU is now sitting at almost room temperature while idling and lower temperatures under load than when it was idling with the previous cooler, so that's good. Sadly, I can already see the plastic push pins will still be a problem in the future, especially since this cooler is very unwieldy to install without completely disassembling the computer and removing the motherboard (which I can't be arsed to do, as I'm sure it would take me ages to figure out how to put the whole thing back together with all the PSU cables, not to mention it'd be quite a hassle).

I don't even think overclocking will be necessary anymore, as apparently my performance issues were all due to the high temperature and even The Witcher 3 is consistently running beautifully with most graphics at Ultra, now. I might give it a shot, though, just to figure out if the bad cooler was also the reason I couldn't overclock the CPU at all.

And to think I was on the verge of (begrudgingly) biting the bullet and buying a new motherboard and CPU along with replacements for all the old parts that wouldn't be compatible with a new motherboard.

Edit: the overclock worked now, so temperatures were definitely the problem. I do appreciate you guys' help, though.