Quick Comparison
| Product | Best For | Est. Price | Rating |
|---|---|---|---|
| Intel Core i7 3770 | Best Overall | ~$35-50 | 4.7/5 |
| Intel Core i5 3470 | Best Budget | ~$15-25 | 4.6/5 |
| Intel Core i7 3770K | Best Premium | ~$45-65 | 4.7/5 |
| Intel Xeon E3 1270 v2 | Best for LGA1155 upgrades | ~$30-45 | 4.5/5 |
| Intel Core i5 2400 | Best Compact | ~$10-18 | 4.6/5 |
Intro
The Dell OptiPlex 790 is a workhorse business desktop built on Intel’s LGA1155 platform. It ships with Sandy Bridge processors ranging from Celeron to Core i7, and with a BIOS update it gains compatibility with Ivy Bridge chips as well. In 2026, these machines remain capable for everyday computing tasks. and a CPU swap is one of the cheapest upgrades you can make to meaningfully improve responsiveness.
The OptiPlex 790 comes in four form factors: Mini Tower, Small Form Factor, Ultra Small Form Factor, and Desktop. The SFF and USFF variants have tighter TDP limits, so CPU selection depends on which chassis you have. This guide covers the five best CPU upgrades for the platform and what to know before you buy.
Top 5 Picks
1. Intel Core i7-2600. The top Sandy Bridge processor and the strongest upgrade for full-tower and mid-tower OptiPlex 790 units. Quad-core with Hyper-Threading gives you eight logical threads at 3.4 GHz base and 3.8 GHz boost. A dramatic step up from stock Pentium or i3 configurations, and readily available on the used market for under $25.
2. Intel Core i7-2600S. The low-power sibling of the i7-2600 at 65W TDP instead of 95W. Designed specifically for the SFF chassis where heat dissipation is constrained. Performance is very close to the standard i7-2600 in everyday use, with the boost clock stepping down only under sustained multi-threaded loads. The correct i7 choice for small form factor units.
3. Intel Core i5-2500. A quad-core Sandy Bridge processor without Hyper-Threading, running at 3.3 GHz base and 3.7 GHz boost. Strong single-threaded performance for the platform and widely available at excellent prices. A practical upgrade for users who do not need maximum multi-threaded headroom and want a cost-effective step up from a dual-core or Pentium.
4. Intel Core i7-3770. Ivy Bridge’s flagship, compatible after a BIOS update. It adds improved power efficiency, better integrated graphics, and a modest IPC uplift over Sandy Bridge at the same clock speeds. If you find one at a good price and have already applied the BIOS update, the i7-3770 is the best-performing processor the OptiPlex 790 can technically run.
5. Intel Core i5-3470. A solid Ivy Bridge quad-core at 3.2 GHz base and 3.6 GHz boost. More power-efficient than comparable Sandy Bridge parts and widely available used. Offers a tangible IPC improvement over Sandy Bridge i5 options and is compatible with the OptiPlex 790 post-BIOS update. Good value if you want Ivy Bridge performance without the i7-3770 cost.
What to Look For
Form factor and TDP. The OptiPlex 790 Mini Tower handles 95W processors without issue. The SFF chassis is limited to 65W parts. look for the S-suffix variants like the i7-2600S or i5-2500S. Installing a 95W CPU in an SFF unit causes thermal throttling and instability.
BIOS version. Ivy Bridge compatibility requires the latest Dell BIOS update for the 790. Update the BIOS before installing any third-generation Intel processor. Sandy Bridge upgrades work without a BIOS change and are the safer route if you want a simpler swap.
RAM configuration. The OptiPlex 790 supports up to 32 GB of DDR3 in four slots. If your unit is running 4 GB or less, a RAM upgrade alongside the CPU will have an equal or greater impact on daily usability. Target 16 GB DDR3-1333 or DDR3-1600 in dual channel.
Thermal paste. When removing the old CPU, clean the heat sink and apply fresh thermal compound. Stock paste on a machine this age is degraded and replacing it will help the new processor maintain boost clocks reliably.
Final Thoughts
The Dell OptiPlex 790 is a limited but upgradeable platform. For most users the Intel Core i7-2600 is the best upgrade. it maxes out Sandy Bridge performance on the standard chassis and costs very little. SFF users should target the i7-2600S to stay within the thermal envelope. If you want to push the platform further, a BIOS update and a used Core i7-3770 brings genuine Ivy Bridge IPC gains.
Combine the CPU swap with a RAM upgrade to 16 GB and an SSD if the machine still runs a spinning drive, and the OptiPlex 790 becomes a capable everyday PC for browsing, productivity, and light media work in 2026.
Frequently asked questions
What is the best CPU upgrade for the Dell OptiPlex 790?+
The Intel Core i7-2600 or i7-2600S are the strongest CPU upgrades for the Dell OptiPlex 790. Both are quad-core LGA1155 processors with Hyper-Threading, giving you eight logical threads. The i7-2600S has a lower TDP suited to small form factor units, while the standard i7-2600 is the better choice for the full-tower or mid-tower chassis variants.
Does the Dell OptiPlex 790 support Ivy Bridge CPUs?+
Yes, with a BIOS update the Dell OptiPlex 790 supports select Ivy Bridge processors. The Core i5-3470 and Core i7-3770 have been confirmed compatible by users after updating to the latest available BIOS version. Always verify compatibility for your specific unit revision before purchasing and update the BIOS before installing the new processor.
Is upgrading the CPU on a Dell OptiPlex 790 worth it in 2026?+
For light tasks like web browsing, document work, and media playback, a CPU upgrade to the i7-2600 or i5-3470 makes a noticeable difference in responsiveness. The platform is limited by DDR3 RAM, a 2.5 Gbps SATA controller, and no PCIe 4.0 support, so do not expect workstation-class performance. As a budget productivity machine, a modest CPU upgrade delivers solid value for under $50.