Buying an RTX 4090 at today’s used-listing price of about $3,217 pays off against Runpod’s $0.74-an-hour secure-cloud rate after roughly 5,000 hours of use, and against its $0.34 community rate after roughly 13,400 hours. Those figures are our arithmetic and they include the electricity the card and its computer draw at the 18.31¢ US average. At four hours a day, that is 3.4 years in the best case and more than nine years in the worst. An RTX 5090 at about $6,086 takes 7,000 to 10,700 hours. Rented GPUs are cheap right now and cards are expensive, so for occasional AI work the break-even point sits far away.
The Prices We Used
Every number below comes from a page we looked at in early October 2026. Card prices move weekly, so treat them as a snapshot.
| Item | Figure | Source |
|---|---|---|
| RTX 4090, 24 GB | $3,217 (lowest average listing) | GPU Poet, October 2026 |
| RTX 5090, 32 GB | $6,086 (lowest average listing) | GPU Poet, October 2026 |
| RTX 4090 power | 450 W graphics power | NVIDIA product page |
| RTX 5090 power | 575 W graphics power | NVIDIA product page |
| Runpod RTX 4090 | $0.34/hr community, $0.74/hr secure | Runpod pricing page |
| Runpod RTX 5090 | $0.69/hr community, $0.99/hr secure | Runpod pricing page |
GPU Poet tracks eBay-style marketplace listings, so these are street prices, not NVIDIA’s list prices. The same tracker showed the 4090’s lowest average at $2,300 in July 2026 and $2,449 in January 2026, so a buyer today is paying roughly 30% more than a few months ago. NVIDIA’s own pages did not show a price, which is why we use the tracker. Vast.ai also lists a 4090 at about $0.36 an hour in the September 2026 snapshot we quote in our GPU rental income guide, which sits close to Runpod’s community rate.
The power figures are NVIDIA’s total graphics power, a ceiling rather than a measurement of every workload. NVIDIA also recommends an 850 W power supply for both cards.
What Running the Card Costs
A card needs a computer around it. We assume 100 W for the rest of the system (our estimate, the same one used in our local LLM cost guide) and charge the EIA’s July 2026 US residential average of 18.31¢ per kWh.
- RTX 4090: (450 W + 100 W) ÷ 1,000 × $0.1831 = about 10.1¢ per hour at full load
- RTX 5090: (575 W + 100 W) ÷ 1,000 × $0.1831 = about 12.4¢ per hour at full load
Power is only charged for hours the card is working, since this guide assumes you use it on demand. A machine left on 24/7 adds idle draw on top, which our gaming PC electricity guide covers.
Break-Even Hours: Buy vs Rent
The formula is price ÷ (rental rate − your electricity cost per hour). Renting has no power bill on your side, so each hour you run your own card saves the rental rate but costs you 10 to 12 cents.
| Card | Rental rate compared | Break-even hours (rent price only) | Break-even hours (power included) | Years at 4 hrs/day | Years at 8 hrs/day |
|---|---|---|---|---|---|
| RTX 4090, $3,217 | $0.34 community | 9,462 | 13,444 | 9.2 | 4.6 |
| RTX 4090, $3,217 | $0.74 secure | 4,347 | 5,032 | 3.4 | 1.7 |
| RTX 5090, $6,086 | $0.69 community | 8,820 | 10,745 | 7.4 | 3.7 |
| RTX 5090, $6,086 | $0.99 secure | 6,147 | 7,024 | 4.8 | 2.4 |
Four hours a day is 1,460 hours a year and eight is 2,920. Both are our assumptions, not usage data. The middle column is what a quick comparison gives you and it understates the true break-even by 14 to 42 percent, because the power bill eats part of the savings.
Electricity Rate Changes the Answer Less Than You Think
Cheap power helps, but only a little. At 10¢ per kWh the 4090’s break-even against the $0.74 secure rate drops from 5,032 to about 4,700 hours, and against the $0.34 community rate from 13,444 to about 11,300. The rental rate and the card price drive the result, not the utility bill. If you want your own rate, our electric bill estimator turns watts into dollars. Rates by state run from 12.72¢ in Louisiana to 48¢ in Hawaii per the same EIA table, so a Hawaii owner breaks even later and a Louisiana owner slightly sooner.
Resale Value Cuts the Hours
A GPU is not consumed when you stop using it. If you can sell the card later, only the loss in value needs to be covered by the hours you run. We do not have a verified resale figure for these cards, so take this as a scenario: if a 4090 resells for half of the $3,217 you paid, the break-even against the secure rate falls from 5,032 hours to about 2,500 (our arithmetic). The risk runs both ways: a card bought after a 30% jump in four months may resell for less if prices settle back.
This is also the best argument for waiting. Someone who bought the 4090 in July at $2,300 breaks even against the secure rate in about 3,600 hours, which is a different decision from today’s 5,032.
When Buying Wins
- You run it most of the day. Training runs, image generation queues, or a local model serving several people push usage toward 8 hours a day, which puts the 4090 under two years against the secure rate.
- You also game or edit video. The card earns its price on the work you were going to do anyway, and the AI use is a bonus.
- You need your data local or the machine always available. A rented instance depends on the provider having capacity when you want it, which we could not check.
- The card you already own. If you have it, the comparison is only electricity versus rental, and your own card wins at almost any rate: about 10 cents an hour against 34 to 74.
When Renting Wins
- Bursty work. A weekend fine-tune, a few hours of experiments, or a one-off render is cheaper rented. Ten hours a month on a 4090 at $0.74 is $7.40.
- You need more than one card’s memory. A 24 GB or 32 GB card is a hard ceiling. Rental lets you pick a larger card for a day instead of buying one. Runpod’s page also lists the RTX A6000 with 48 GB at $0.53 secure and $0.33 community per hour.
- Prices are volatile. With card prices up sharply in a few months, renting avoids buying at a peak.
Costs That Are Not in the Table
Buying adds a computer, a power supply rated for the card, and cooling, none of which we priced above. Renting adds storage and data transfer fees on some providers, plus the time spent setting up an instance each session, so read the pricing page’s line items before assuming the hourly rate is the whole bill. Neither side includes your time, which we have left out.
If you are thinking about earning money from the card instead of just using it, the math is different and mostly worse. Our GPU rental income calculator runs that case.
Bottom Line
At October 2026 prices, an RTX 4090 bought for $3,217 breaks even against Runpod’s rates after about 5,000 hours (secure cloud) to 13,400 hours (community cloud) once power is counted, and a $6,086 RTX 5090 needs 7,000 to 10,700 hours. If you will use a GPU four hours a day or less, rent. If you will use it eight hours a day, or you also game on it, buying starts to make sense, ideally after card prices settle. Check your own numbers before you click buy, and remember that the rental rate, not your electricity rate, decides the answer.
FAQ
Is it cheaper to buy a GPU or rent one in the cloud?
For occasional use, renting is cheaper. At current prices a $3,217 RTX 4090 needs about 5,000 hours of use to beat Runpod’s $0.74 secure rate and about 13,400 hours to beat its $0.34 community rate, counting power at 18.31¢ per kWh. Heavy daily use or gaming on the same card shortens that.
How many hours until an RTX 4090 pays for itself versus cloud rental?
About 5,032 hours against the $0.74 secure rate and about 13,444 against the $0.34 community rate. At four hours a day that is 3.4 and 9.2 years. These are our arithmetic from GPU Poet’s price and Runpod’s listed rates.
How much electricity does an RTX 4090 use compared with an RTX 5090?
NVIDIA lists 450 W for the 4090 and 575 W for the 5090 as total graphics power. With about 100 W for the rest of the computer, that is roughly 10.1¢ and 12.4¢ per hour at the 18.31¢ US average. Real draw varies by workload, so treat those as upper estimates.
Does resale value change the break-even?
Yes, a lot. If you sell the card later, you only have to recover the loss in value, not the full price. We do not have a verified resale figure, but if a card resold for half its price, the break-even hours would roughly halve. Card prices have moved about 30% in four months, so the resale side carries real risk.