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Should I Risk It?

Posted: Tue Jul 02, 2019 9:15 am
by zacharyt1122
Ok, so I'm trying to be super lazy and cheap. I have an EVGA Supernova 550 power supply currently powering an 8700K with a Kraken X62, MSI 1060, 16 gigs RAM, and a 512 gig Samsung SSD. I have an EVGA 1080Ti SC2 lying around. I know they recommend a 650 watt powersupply for it. Do you think I'd be safe to run the 1080Ti knowing these specs?

Re: Should I Risk It?

Posted: Tue Jul 02, 2019 9:23 am
by DPete27
Without overclocking, you're possibly looking at 400W system power draw with an 8700K + 1080Ti.

Re: Should I Risk It?

Posted: Tue Jul 02, 2019 9:44 am
by Waco
Seems like no real risk to me.

Re: Should I Risk It?

Posted: Tue Jul 02, 2019 10:12 am
by zacharyt1122
Guess it would have been helpful to say that I'm running XMP, so my processor is sitting at 4.5 GHz IIRC. Well I'll give it a shot then!

Re: Should I Risk It?

Posted: Tue Jul 02, 2019 12:11 pm
by DPete27
XMP isn't related to (and doesn't affect..) your CPU frequency.

Re: Should I Risk It?

Posted: Tue Jul 02, 2019 1:32 pm
by derFunkenstein
DPete27 wrote:
XMP isn't related to (and doesn't affect..) your CPU frequency.

On some motherboards, enabling XMP also turns on MCE, which would have the effect he's describing. It's a dirty trick mobo manufacturers play on reviewers.

Re: Should I Risk It?

Posted: Tue Jul 02, 2019 2:06 pm
by zacharyt1122
So I have a 6900K machine with XMP and CPU-Z reports 4.0GHz, and my 8700K machine with XMP reports 4.5GHz. I know XMP isn't "overclocking" but I'm just a tinkerer with computers, I really don't worry about manual overclocking.

Edit: My 6900K machine is an Asus X99 Deluxe and my 8700K is an Asrock Z370 itx board, so I believe both boards do turn on MCE.

Re: Should I Risk It?

Posted: Wed Jul 03, 2019 1:57 pm
by zacharyt1122
Thanks for the input, I was able to install it without any issues. DPete27 was on the money, I hooked it up to my 6900K machine and it was never hit 400 watts according to Corsair Link after 30 minutes of 3dMark. It went into my 8700K machine without any issues.

Re: Should I Risk It?

Posted: Fri Jul 26, 2019 5:24 am
by TrevX
zacharyt1122 wrote:
Thanks for the input, I was able to install it without any issues. DPete27 was on the money, I hooked it up to my 6900K machine and it was never hit 400 watts according to Corsair Link after 30 minutes of 3dMark. It went into my 8700K machine without any issues.


Sorry, this is my first post. My name is Trev.
I just wanted to ask as I'm currently in similar situation to you - is this still running ok for you? (No overheating or performance issues?)

Re: Should I Risk It?

Posted: Fri Jul 26, 2019 6:57 am
by dragontamer5788
DPete27 wrote:
Without overclocking, you're possibly looking at 400W system power draw with an 8700K + 1080Ti.


Note: power-supplies need to be rated for maximum instantaneous power draw, and not average power draw of your system. You should have a significant safety-factor for this reason.

zacharyt1122 wrote:
Thanks for the input, I was able to install it without any issues. DPete27 was on the money, I hooked it up to my 6900K machine and it was never hit 400 watts according to Corsair Link after 30 minutes of 3dMark. It went into my 8700K machine without any issues.


Do you have an oscilloscope? You need to be measuring instantaneous power-usage, not average wall power usage.

Re: Should I Risk It?

Posted: Fri Jul 26, 2019 10:52 am
by ludi
In my own case, I *do* have an oscilloscope, but I wouldn't be likely to break out for the use case described here. If the power draw is staying well below the maximum under a sustained heavy load AND the system isn't mysteriously crashing from time to time, then the power supply is likely adequate.

Re: Should I Risk It?

Posted: Sat Jul 27, 2019 11:25 am
by zacharyt1122
My system has been running perfectly, I have it in a NZXT H200i so I was a little concerned about heat, but after stress testing the temps never went above 72. And I have a front mounted radiator literally like an inch from the GPU, and temps have been perfect. Now I did leave it at stock, no OC or anything, but I really don't need the extra power for the games I'm playing currently.

Re: Should I Risk It?

Posted: Mon Jul 29, 2019 9:59 pm
by DPete27
dragontamer5788 wrote:
DPete27 wrote:
Without overclocking, you're possibly looking at 400W system power draw with an 8700K + 1080Ti.


Note: power-supplies need to be rated for maximum instantaneous power draw, and not average power draw of your system. You should have a significant safety-factor for this reason.

I absolutely agree.

Re: Should I Risk It?

Posted: Tue Jul 30, 2019 1:13 pm
by dragontamer5788
ludi wrote:
In my own case, I *do* have an oscilloscope, but I wouldn't be likely to break out for the use case described here. If the power draw is staying well below the maximum under a sustained heavy load AND the system isn't mysteriously crashing from time to time, then the power supply is likely adequate.


Well you'd need an overpowered powersupply + oscilloscope to really test it out.

I agree it isn't worth the effort. Which is why its just a safer idea to buy +100W or +150W over what you expect to need. Going with a sizable "safety factor" is the easiest way of doing things. Otherwise, you need to guess-and-check with a variety of workloads. I mean, honestly, we're talking about saving $10 to $20 at the most. Spending +$10 for an oversized PSU is way easier than performing all the QA steps needed to prove that a lower PSU is usable.