Optiplex 745 Small Form Factor - R7 250

[polis_putrus]

Is the R7 250 2GB Low Profile (65w) the best graphics card for the Optiplex 745 Small Form Factor 275w, I currently have an R5 240 1GB Low Profile (50w). Thanls for any help

 

[King_V]

Note that there are two variants of the R7 250, one with GDDR5 memory, and one with DDR3 memory. The GDDR5 variant is preferable, as it's faster.

Having looked at a couple of images, while you need a low profile card, it seems that your PCIe slot is positioned so that you could manage a double-slot card (ie: the heatsink is too tall to fit neatly in a single slot profile).

If this is correct:
https://www.aliexpress.com/item/2015-Supply-H275E-00-For-Dell-XPS-200-210-SFF-275-Watt-Power-Supply-RM117/32388360947.html

Then, while your PSU is 275W, you only have a max of 204W available on the 12V rail. That's a little concerning. Also, you don't have a PCIe power connector, so you must stick with a card that doesn't require one.


The R7 250E is slightly faster than the R7 250 GDDR5 (it's basically a rebranded HD 7750), and consumes slightly less power (55w). Sapphire calls it the R7 250 Low Profile. I have one of those (though no longer use it), and used it on a PC with a 4th gen Pentium CPU, and a PSU of 220W (but offered 216W on the 12V rail). However, this had the PCIe slot all the way at the end of the board, leaving no room for a taller cooler - the entire thing had to fit in a single-slot height. I *think* the 250E is another one that may have DDR3 vs GDDR5 variants.

The GTX 750 (55W) and 750Ti (60W) should both work for you as well. They are definitely faster than the R7 250.

A GT 1030 is also worth considering, as it has low power draw (30W) and is available in low-profile form. Sometimes Dells are fussy about newer video cards, though, so it may not play nicely with the GT 1030. The GT 1030 is a little bit slower than the GTX 750, but a little faster than the R7 250 and 250E.

The legacy GPU hierarchy chart on this page serves as a pretty good guide.

https://www.tomshardware.com/reviews/gpu-hierarchy,4388.html

 

[polis_putrus]

The PSU you linked is correct, Im planning to buy the R7 250 rather than the GTX 750 is bcause it is much more cheaper on ebay, and why is it concerning that I only have 204W avalable on the 12V rail isnt that more than enough, also what concerns me much more is that I will also upgrade my CPU to a Core 2 Quad Q6700, Final upgrades will be Core 2 Quad q6700, R7 250, 8GB ram, 1TB harddrive. Will this work.
I will go with the GDDR3 if there is a cheap one avalable on ebay, and the GT 1030, I never even thought of, thanks for showing it to me, I will consider it but it is pretty expensive on ebay $80 cheapest. I can afford about $30-$40 BUT I would love to buy the 1030 I watched gameplay videos with it and it goes much faster than the R7 250.

 

[King_V]

Make sure it's GDDR5. DDR3 is much slower. I don't think there's a GDDR3. Also, even with the 1030, there's a DDR4 vs a GDDR5 - avoid the DDR4.

The system I had was using a Pentium G3220, which was a 55W CPU. The Core 2 Quad 6700 is 95W-105W (Wikipedia says 95W, Intel's specifications page says 105W).
https://en.wikipedia.org/wiki/List_of_Intel_Core_2_microprocessors#Core_2_Quad
https://ark.intel.com/products/30790/Intel-Core2-Quad-Processor-Q6700-8M-Cache-2_66-GHz-1066-MHz-FSB

My own total was thus 55W for CPU, 55W for the R7 250E, putting me at 110W, leaving me another 106W maximum remaining for the motherboard, optical drive, hard drive, RAM, CPU fan, etc. which gave me a pretty comfortable margin.

In your system, assume worst case 105W, a GPU of 65W would put you at 170W. That leaves only 34 remaining for the motherboard, RAM, hard drive, fans, etc. I think that's pushing things too close to the edge. An HD7750 or R7 250E would give you 10W more of breathing room, but it's still riskier than I'm comfortable with. It's generally a bad idea to be running the PSU at its maximum limit continuously.

Because of the lower power consumption, if it's possible to save up until you can afford the 1030, I would recommend doing so. I am not 100% sure if the Dell BIOS will accept it, and haven't been able to find a definite answer, but this post about Linux installations seems to imply that the person who posted it has successfully used a 1030 in the Optiplex 745. It's not clear if he's using the MiniTower, Desktop, or SFF variety, though.

https://pcpartpicker.com/forums/topic/273115-how-to-install-a-linux-distribution

 

[polis_putrus]

I will be sure to check the GDDR also you add up your watts and at the end you say "106W maximum remaining for the motherboard, optical drive, hard drive, RAM, CPU fan" I see you said motherboard, Ive been trying soo hard to find out how much watts a motherboard uses, and yeah I know its risky but look:

Core 2 Quad Q6700 - 95 watts
Nvdia GT 1030 - 30 watts
Ram 7GB - 33 wats
1TB Hard Drive - 11 watts
2 or 3 small fans - 4 watts

All added up to 173 watts, that means approximately 102 watts free out of 275 watts

Woudnt this be safe or is something incorrect.

 

[King_V]

I think the power from RAM usage is much lower than you're showing. Maybe 10W total. I seem to recall it was something like 4W per stick, but I'm not sure.

I've seen estimates of 20-50W for motherboards, depending on how big they are and how many features they have. I've never been able to get a more solid number, but I assume the SFF types of machines will be on the lower end of that.

The problem is that the 5V and 3.3V rails are mostly not part of the equation. You have to look at all of the 12V rails, and see how many amps they have.

In the case of your power supply, it shows: 12V ===/ 17A

12 * 17 = 204, thus 204 Watts available.

Assuming that RAM+Motherboard is 40W, and using the rest of the numbers you have listed above, we come to 180W, which leaves you a margin of 24W. I think that's workable.

But, if Intel's page is right about the Q6700, then that's 10 more W (admittedly, that's probably only when the CPU is being maxed out), also MAYBE if the MB is 10W higher than my assumption, then we're talking 200W, with a VERY uncomfortably small margin of only 4W.

On the other hand, the HDD is probably rarely running 100% when doing something that's both CPU and GPU intensive.

If this is your only machine that you need to rely on, then it's risky. What CPU do you have currently?

 

[polis_putrus]

I got the RAM wattage information from here I press calculatr BEFORE PUTTING ANY SPECS and it says Load wattage 113 watts, THEN I put in my ram specs and it says 146 watts load wattage, 146-113= 33 watts so thats how I got that

Its DDR2 4X2GB I have 8GB RAM

I currently have a Core 2 Duo E6400 and I think your right the Quad is 105 watts, forgot where I got the 95 watts from
Oh and sorry guys It says in the calculation 7GB RAM I used to have 7GB but replaced the 1GB stick with a 2GB but the 33 watts still stays the same, I calculated the 33 watts with 8GB RAM sorry.

 

[polis_putrus]

I think the power from RAM usage is much lower than you're showing. Maybe 10W total. I seem to recall it was something like 4W per stick, but I'm not sure.

I've seen estimates of 20-50W for motherboards, depending on how big they are and how many features they have. I've never been able to get a more solid number, but I assume the SFF types of machines will be on the lower end of that.

The problem is that the 5V and 3.3V rails are mostly not part of the equation. You have to look at all of the 12V rails, and see how many amps they have.

In the case of your power supply, it shows: 12V ===/ 17A

12 * 17 = 204, thus 204 Watts available.

Assuming that RAM+Motherboard is 40W, and using the rest of the numbers you have listed above, we come to 180W, which leaves you a margin of 24W. I think that's workable.

But, if Intel's page is right about the Q6700, then that's 10 more W (admittedly, that's probably only when the CPU is being maxed out), also MAYBE if the MB is 10W higher than my assumption, then we're talking 200W, with a VERY uncomfortably small margin of only 4W.

On the other hand, the HDD is probably rarely running 100% when doing something that's both CPU and GPU intensive.

If this is your only machine that you need to rely on, then it's risky. What CPU do you have currently?

Are you sure its risky because you guys say only 204 watts are avalable and my watts added up were 173 watts leaving 30 or so for the motherboard, the ram I added into the calculation so the 30 watts left over is for the motherboard only wouldnt that be enough, BECAUSE all the watts that you see, is MAX it is if I were to use the computer to the MAX which I wont because I will be gaming but with low graphics, so Im sure I will be safe.

 

[King_V]

It's still under the max, true. There's still some risk, but if you're SURE the GPU and CPU won't be pushed to the max, then it might be safe.

 

[polis_putrus]

Yes this is my only machine I can work with, and no I will not be using the computer to the max I will be gaming on fairly low settings, and I will constantly be checking temperatures with HW Monitor. If the watts went over would the power supply burn or would the computer shut down or would the part that needs the power like the CPU or GPU get damaged. Also I never really thought about the different rails, I will go ahead and risk it, and all the calculations, are with the 1030 I can't imagine what would happen if I bought the R7 250 (65w) card, now my only best and safest option would be the 1030 it will take a while for me to actually get enough money so when I'm done with the upgrade I will let you know what happens, if it worked, how much better it is, etc Thanks for all your help and thanks for letting me know about the 1030, I will check this thread from time to time, Thanks

 

[King_V]

You're welcome. It's unfortunate that there aren't (as far as I know) more powerful PSUs available in the form factor that these Dell SFF cases use.

I have never experienced a PSU failure, but I am told it CAN damage things. I would think most likely the PSU would just burn out, but I've read it might also damage components.

I did have a friend whose PSU failed, and the 4-pin connector, the white plastic had partially blackened on the motherboard. However, the connector was still fine, and a replacement PSU did the trick.

I'd definitely be interested in learning how this goes, both short and long term. I would definitely be cautious.

I did see posts on Dell's forums of people using the Q6700 successfully, but nothing that said about what video card they upgraded to, or if they did at all. Unfortunately, while some people specified whether they were using the SFF case or the MT (mini-tower) others did not specify.

While you're waiting to get the money - I'd recommend doing searches on Optiplex 745 upgrades, gathering together as much info as you can about who used what, how successful it was, etc.

 

[polis_putrus]

Yeah I know I see people upgrading their CPU but those who upgrade their CPU never also upgrade the graphics, very weird since the onboard graphics are terrible. If my PSU fails, then shit, it will be ok, but it will just take some time to make money to buy a new one, also you know the PSU wires, what if I bought a PSU that DOESNT fit but has the EXACT same wires as my original PSU but has more watts like say 400w would that work, doesnt fit, has same wires the PC needs, and has more watts.

 

[King_V]

I've heard of people doing that - getting a power supply that doesn't fit, and using it externally. It should be workable, but I have no experience doing that.

BUT - you would probably need to add a fan to the case to pull air out, to make up for the PSU's exhaust fan no longer being present in the case.

 

[polis_putrus]

I've heard of people doing that - getting a power supply that doesn't fit, and using it externally. It should be workable, but I have no experience doing that.

BUT - you would probably need to add a fan to the case to pull air out, to make up for the PSU's exhaust fan no longer being present in the case.

Good to know I will try to find one that is smaller rather than bigger. Thanks