CPU Comparison
Intel Core i5-8420T vs Intel Core i9-9900T
A side-by-side comparison of specs, performance and value. The Intel Core i5-8420T is a low-power desktop processor part of the 8th generation Coffee Lake family. Released in September 2018, it is a slight revision of the i5-8400T. Built on the 14nm process, it features 6 cores and 6 threads. The 'T' suffix indicates a 35W TDP, making it suitable for small form factor and energy-efficient systems. The base clock is 1.8 GHz, with a maximum turbo boost of 3.4 GHz, offering a minor bump over its predecessor. It includes 9 MB of Intel Smart Cache and supports dual-channel DDR4 memory up to 2666 MT/s. The integrated Intel UHD Graphics 630 handles standard display output. With 16 PCIe 3.0 lanes, it provides sufficient bandwidth for typical desktop expansions. Compatible with LGA 1151 sockets on 300-series chipsets, the i5-8420T is an OEM-focused chip designed for corporate environments and compact PCs where power efficiency is paramount.
The Bottom Line
Overview & Launch
Specifications Compared
Performance Compared
Productivity
6 cores provide good office performance, but single-core is limited.
Strong multi-threaded capability for office applications and light creative work.
Gaming
Marginally better than 8400T, but still too slow for modern gaming.
Lower clocks limit high-refresh-rate gaming, but integrated graphics handle casual titles.
Virtualization
Suitable for basic VMs, but lacks threads.
Sufficient for basic virtualization tasks, but not ideal for heavy VM workloads.
Efficiency
Excellent 35W efficiency.
Exceptional power efficiency is the primary design goal and key strength.
Specialized Performance
AI / ML
- No dedicated AI hardware.
- Slow CPU inference.
- No dedicated AI acceleration
- Only suitable for lightweight, CPU-based inference
Content Creation
Gaming
- Low clocks limit high-refresh gaming.
- Integrated graphics are weak.
- Needs a discrete GPU for any real gaming.
- Not intended for serious gaming
- Limited by low base and boost clocks
- UHD Graphics 630 suitable only for very light or older games
Industry Impact
Best CPU by Use Case
Target Audience
Strengths & Weaknesses
Pros
- Low 35W TDP
- 6 cores for multi-tasking
- Runs cool and quiet
- Good for basic office use
Cons
- Very similar to 8400T
- Locked multiplier
- No Hyper-Threading
- Hard to find retail, OEM only
Pros
- Exceptionally low 35W TDP for quiet and cool operation
- Full 8-core/16-thread Coffee Lake performance
- Configurable down to 25W for embedded or low-power designs
- Integrated graphics for display output without a GPU
- Often available at a deep discount on the used market
Cons
- Significantly lower clock speeds than standard desktop CPUs
- Locked multiplier limits performance tuning
- On the older LGA1151 platform with no future upgrade path
- Discontinued, with limited availability and support
- Not competitive for gaming or performance-critical tasks
Competitors & Alternatives
Intel Core i5-8420T
- Compare head-to-headIntel Core i5-8400TRival
Low Power Desktop
- AMD Ryzen 5 2400GERival
Low Power Desktop
- Compare head-to-headIntel Core i5-8500TRival
Low Power Desktop
- AMD Ryzen 3 2200GERival
Budget Low Power
- Compare head-to-headIntel Core i3-8100TRival
Budget Low Power
- AMD Ryzen 5 3400GEAlt
Better integrated graphics.
Modern alternative with much better IPC.
Compare head-to-head- AMD Ryzen 5 5600GEAlt
Better efficiency and multi-core.
Intel Core i9-9900T
- AMD Ryzen 7 2700XRival
High-Performance Desktop
- Intel Core i7-9700TRival
Power-Optimized Desktop
- Compare head-to-headIntel Core i5-9500TRival
Power-Optimized Desktop
- AMD Ryzen 5 3400GERival
Power-Optimized Desktop APU
- Compare head-to-headIntel Core i9-9900Rival
Standard Desktop
Much higher performance for gaming and productivity, but requires better cooling and power.
Compare head-to-headFar superior performance, modern platform, and efficiency; a better new buy.
Compare head-to-head- AMD Ryzen 7 5700GAlt
Strong APU with better integrated graphics and comparable efficiency.
Excellent single-thread performance and efficiency for basic tasks on a modern platform.
Compare head-to-head- AMD Ryzen 5 5600Alt
Better overall performance and value on a more modern platform.
Our Verdict on Each
A modest refresh of the 8400T, offering slightly higher clocks in the same 35W envelope, primarily for OEM systems.
Best for: Finding a cheap used OEM PC with this chip for basic office work.
Read the full reviewA capable 8-core CPU that trades raw clock speed for significantly lower power consumption, ideal for specific use cases where efficiency and thermals matter more than maximum performance.
Best for: Building or upgrading a very quiet, small form factor PC where low power and heat are critical, and the CPU can be found at a significant discount.
Read the full reviewFrequently Asked Questions
Which is better, Intel Core i5-8420T or Intel Core i9-9900T?
Based on our editorial ratings, the Intel Core i9-9900T comes out ahead with a score of 7.5/10. That said, the best choice depends on your workload — check the spec and performance breakdown above for gaming, productivity and efficiency differences.
Which is faster for gaming, Intel Core i5-8420T or Intel Core i9-9900T?
For gaming, the Intel Core i9-9900T leads with a gaming performance score of 70/100 among Intel Core i5-8420T and Intel Core i9-9900T.
Do Intel Core i5-8420T and Intel Core i9-9900T use the same socket?
No. They use different sockets (Intel Core i5-8420T: LGA 1151, Intel Core i9-9900T: FCLGA1151), so each needs a compatible motherboard.
Which has more cores?
The Intel Core i9-9900T has the most cores. Core counts: Intel Core i5-8420T (6 cores), Intel Core i9-9900T (8 cores).
Which is faster in multi-core benchmarks?
The Intel Core i9-9900T posts the highest multi-core benchmark score. Multi-core results: Intel Core i5-8420T (8,600), Intel Core i9-9900T (13,086). Benchmark figures are approximate and workload-dependent.