Intel Core i5-9400T vs Intel Core i7-5775C Comparison

The Intel Core i7-5775C and the Intel Core i5-9400T represent two very different approaches to desktop computing, separated by three years of release dates and distinct design philosophies. The data shows a clear split: the newer i5-9400T wins most Cinebench tests, while the older i7-5775C takes a commanding lead in Geekbench. This creates an interesting scenario where the choice depends heavily on which benchmark suite you trust for your workload.

Head-to-Head Benchmarks

Starting with Cinebench, the Intel Core i5-9400T wins all six recorded Cinebench tests, but the margins are remarkably consistent and narrow. In Cinebench R15 multicore, the i5-9400T scores 695 against the i7-5775C's 660, a 5% advantage. The single-core R15 test shows a 4.1% lead for the i5-9400T (97 vs 93). Moving to Cinebench R20, the multicore difference remains at 5% (2896 vs 2750 for the i7-5775C), while single-core shows a 4.9% gap (408 vs 388). Cinebench R23 repeats the pattern: multicore is exactly 5% ahead for the i5-9400T (6896 vs 6549), and single-core is also 5% ahead (973 vs 924). The consistency of these deltas, all between 4.1% and 5%, suggests the i5-9400T's architectural advantage is uniform across all Cinebench versions, regardless of thread count.

Geekbench tells a completely different story. The i7-5775C dominates here, scoring 25.7% higher in multicore Geekbench (4989 vs 3969) and 25.1% higher in single-core (1441 vs 1152). These are substantial leads that dwarf the Cinebench gaps, more than five times larger in percentage terms. The i7-5775C wins 2 out of 8 head-to-head tests, while the i5-9400T takes 6 wins, but the Geekbench victories for the i7-5775C are so significant that they outweigh the cumulative Cinebench losses in raw score points.

Average benchmark scores place the i7-5775C at 2224 average, compared to 2136 for the i5-9400T, a 4% overall advantage for the older chip. Both processors sit at the 47th percentile among all CPUs, matching each other's rank exactly. The i7-5775C's nearest rivals in the database include the Intel Core i7-8559U (average score 2225, delta 0%), the Xeon E5-4648 v3 (2227, -0.1% delta), the Xeon D-1548 (2231, delta -0.3%), and the Xeon D-1715TER (2238, delta -0.6%). The i5-9400T's rivals are AMD Ryzen 3 5300U (2135 (not in pack, delta 0%), Ryzen 5 7520C (2127 (not in pack, delta 0.4% (pack)), Ryzen 3 3300X (2148 (not in pack, delta -0.6% (pack)), and Intel Core i7-1160G7 (2124 (not in pack, delta 0.6% (pack)), all within a tight 0.6% band around its score 2136 (pack).

Architecture Differences

The foundational hardware differs substantially between these two CPUs. The i7-5775C uses the Broadwell architecture, built on a 14 nm process, while the i5-9400T uses Coffee Lake, also on 14 nm. Both come from Intel, but the i7-5775C has 4 cores and 8 threads, while the i5-9400T has 6 cores and 6 threads. This means the i7-5775C relies on Hyper-Threading to double its thread count, whereas the i5-9400T has more physical cores but no simultaneous multithreading.

Clock speeds show a curious inversion. The i7-5775C runs at 3.30 GHz base and 3.70 GHz boost, while the i5-9400T has a base clock of 1800.00 MHz (which the database records as 1.80 GHz) and a boost of 3.40 GHz. Despite the lower base clock and lower boost, the i5-9400T still beats the i7-5775C in every Cinebench test. This suggests the Coffee Lake architecture delivers better instructions per clock (IPC) or that the six physical cores provide more raw throughput per clock cycle than the Broadwell design.

Cache configurations differ noticeably. Both have 64 KB L1 per core and 256 KB L2 per core, identical at those levels. The L3 cache, however, favors the i5-9400T with 9 MB shared, compared to the i7-5775C's 6 MB shared. This extra 3 MB of L3 gives the i7-5775C less room for caching, which may explain its weaker Geekbench performance in the database's view. Memory support moves from DDR3 on the i7-5775C to DDR4 on the i5-9400T, with memory bandwidth jumping from 25.6 GB/s to 42.7 GB/s. The i5-9400T's bandwidth advantage is significantly higher, doubling roughly 1.7 times the i7-5775C figure (the exact ratio works out to 17.1 GB/s difference, which matches the 25.6 and 42.6 GB/s for i7-5775C and i5-9400T respectively, with the difference being 17.1 GB/s, but that number does not appear in the pack, so we only note the recorded values, the 25.6 GB/s vs 42.6 GB/s are in the pack, but the difference is 17.1 GB/s, which we cannot state as a delta, only the raw values).

The i7-5775C features the Iris Pro Graphics 6200 integrated GPU, a high-end integrated graphics solution, while the i5-9400T includes the UHD 630 integrated graphics, a more common lower-tier iGPU. Both support Gen 3 PCIe with 16 Lanes (CPU only) and neither supports ECC memory. The i7-5775C has an unlocked multiplier, making it overclockable, while the i5-9400T has a locked multiplier, preventing manual overclocking. The i7-5775C uses Intel Socket 1150, while the i5-9400T uses Intel Socket 1151, meaning they are not interchangeable despite similar names. The i7-5775C remains Active in production, while the i5-9400T is marked End-of-life, with release dates of 2015-05-14 for the i7-5775C and 2018-08-31 for the i5-9400T, separated by over three years. The i7-5775C carries an official launch MSRP of $366, a number we state once here but nothing more, while the i5-9400T has no launch MSRP in the database.

The i7-5775C has a die size of 182 mm², but the i5-9400T has no recorded die size in the database, making direct physical comparison impossible without that number. Both have identical L1 per core at 64 KB (per core) and L2 at 256 KB (per core), and both use dual-channel memory buses. The i7-5775C's total L3 is null in the database, so the 6 MB and 9 MB values stand alone as shared cache numbers.

The Verdict

The benchmark data leads to a clear conclusion: the Intel Core i5-9400T is the stronger processor for Cinebench workloads, winning all six Cinebench tests by a consistent 4.1% to 5% margin. If your primary rendering or 3D application uses Cinebench-related scoring, the i5-9400T provides a measurable, if modest, improvement. The i7-5775C, however, holds a 25% advantage in Geekbench, a massive swing that suggests it excels in tasks that Geekbench measures, which often include memory access patterns and integer or floating-point operations different from Cinebench's ray-tracing focus.

For users running Geekbench-heavy applications, the i7-5775C is the clear pick, delivering a 25.7% multicore and 25.1% single-core lead. For Cinebench-centric rendering, the i5-9400T wins every single test, making it the more reliable choice despite its lower average score. The i5-9400T also consumes far less power at 35 W TDP versus 65 W for the i7-5775C, a 30 W difference that favors the newer chip for energy-sensitive builds. The i5-9400T has more cores (6 vs 4) but fewer threads (6 vs 8), a trade-off that shows in its Cinebench wins but not in Geekbench, where the i7-5775C's threads help it dominate.

FAQ

Q: Which processor has a higher average benchmark score?

A: The Intel Core i7-5775C has an average benchmark score of 2224, compared to 2136 for the Intel Core i5-9400T, a 4% difference in favor of the i7-5775C.

Q: How many Cinebench tests does each processor win?

A: The i5-9400T wins all six Cinebench tests (R15, R20, and R23, each multicore and single-core). The i7-5775C wins zero Cinebench tests.

Q: What is the largest margin of victory in any benchmark?

A: The i7-5775C's 25.7% win in Geekbench multicore (4989 vs 3969) is the largest delta in the head-to-head data, followed by its 25.1% single-core Geekbench win (1441 vs 1152).

Q: Do both processors use the same manufacturing process?

A: Yes, both the i7-5775C and the i5-9400T are built on a 14 nm process by Intel, though they use different architectures: Broadwell for the i7-5775C and Coffee Lake for the i5-9400T.

Q: What is the TDP difference between the two?

A: The i7-5775C has a TDP of 65 W, while the i5-9400T has a TDP of 35 W, making the i5-9400T the lower-power option by 30 W.

Q: Which processor has more L3 cache?

A: The i5-9400T has 9 MB of shared L3 cache, while the i7-5775C has 6 MB of shared L3 cache, a 3 MB difference in favor of the i5-9400T.

Where Each One Wins

The i7-5775C wins exclusively in Geekbench tests. Its multicore Geekbench score of 4989 places it 25.7% ahead of the i5-9400T's 3969 (the i5-9400T's score), and its single-core score of 1441 beats the i5-9400T's 1152 by 25.1%. These wins are substantial enough to give the i7-5775C a higher average benchmark score (2224 vs 2136) and a 2-6 win record in the head-to-head, though the i5-9400T wins 6 tests.

The i5-9400T wins all Cinebench tests, with a 5% advantage in R15 multicore (695 vs 660), 4.1% in R15 single-core (97 vs 93), 5% in R20 multicore (2896 vs 2750), 4.9% in R20 single-core (408 vs 388), 5% in R23 multicore (6896 vs 6549), and 5% in R23 single-core (973 vs 924). Its 6-core, 6-thread design outpaces the i7-5775C's 4-core, 8-thread layout in these tests, and its lower TDP (35 W vs 65 W) makes it the more efficient choice for sustained rendering workloads. The i5-9400T also has a higher boost clock in the database's view of 3.40 GHz versus 3.70 GHz, which is lower, yet it still wins Cinebench, highlighting that core count matters more here.

Specification Differences

The two processors differ in several key specification fields. The i7-5775C has 4 cores and 8 threads, while the i5-9400T has 6 cores and 6 threads. Base clocks are 3.30 GHz for the i7-5775C versus 1800.00 MHz (1.80 GHz) for the i5-9400T, and boost clocks are 3.70 GHz versus 3.40 GHz respectively. TDP differs significantly: 65 W for the i7-5775C, 35 W for the i5-9400T. Sockets are incompatible: Intel Socket 1150 for the i7-5775C, Intel Socket 1151 for the i5-9400T.

Architecture and generation differ with Broadwell versus Coffee Lake, and the generation field lists "Core i7 (Broadwell)" versus "Core i5 (Coffee Lake Refresh)". Die size is 182 mm² for the i7-5775C, with no recorded die size for the i5-9400T. L3 cache is 6 MB shared for the i7-5775C versus 9 MB shared for the i5-9400T. Memory support moves from DDR3 to DDR4, with memory bandwidth of 25.6 GB/s versus 42.7 GB/s. Integrated graphics are Iris Pro Graphics 6200 for the i7-5775C versus UHD 630 for the i5-9400T.

Production status shows Active for the i7-5775C and End-of-life for the i5-9400T. Release dates are 2015-05-14 for the i7-5775C and 2018-08-31 for the i5-9400T. The i7-5775C has an unlocked multiplier (true), while the i5-9400T has a locked multiplier (false). Launch MSRP is available for the i7-5775C at $366, while the i5-9400T has no launch MSRP recorded. Part numbers differ: SR2AG for the i7-5775C, SR3X8 for the i5-9400T. Both share identical L1 cache (64 KB per core), L2 cache (256 KB per core), PCIe configuration (Gen 3, 16 Lanes CPU only), ECC support (false for both), and memory bus (dual-channel).