i7-1255U vs i5-8400H

Primary details

Comparing Core i5-8400H and Core i7-1255U processor market type (desktop or notebook), architecture, sales start time and price.

Place in the ranking	1254	893
Place by popularity	not in top-100	74
Market segment	Laptop	Laptop
Series	Intel Core i5	Intel Alder Lake-M
Power efficiency	10.06	53.60
Architecture codename	Coffee Lake-H (2018−2019)	Alder Lake-U (2022)
Release date	2 April 2018 (6 years ago)	23 February 2022 (2 years ago)
Launch price (MSRP)	$250	no data

Detailed specifications

Core i5-8400H and Core i7-1255U basic parameters such as number of cores, number of threads, base frequency and turbo boost clock, lithography, cache size and multiplier lock state. These parameters indirectly say of CPU speed, though for more precise assessment you have to consider their test results.

Physical cores	4 (Quad-Core)	10 (Deca-Core)
Threads	8	12
Base clock speed	2.5 GHz	1.7 GHz
Boost clock speed	4.2 GHz	4.7 GHz
Bus type	DMI 3.0	no data
Bus rate	4 × 8 GT/s	no data
Multiplier	25	no data
L1 cache	64K (per core)	80K (per core)
L2 cache	256K (per core)	1.25 MB (per core)
L3 cache	12 MB (shared)	12 MB (shared)
Chip lithography	14 nm	Intel 7 nm
Die size	126 mm2	no data
Maximum core temperature	100 °C	100 °C
Maximum case temperature (TCase)	72 °C	no data
64 bit support	+	+
Windows 11 compatibility	+	+

Compatibility

Information on Core i5-8400H and Core i7-1255U compatibility with other computer components: motherboard (look for socket type), power supply unit (look for power consumption) etc. Useful when planning a future computer configuration or upgrading an existing one. Note that power consumption of some processors can well exceed their nominal TDP, even without overclocking. Some can even double their declared thermals given that the motherboard allows to tune the CPU power parameters.

Number of CPUs in a configuration	1 (Uniprocessor)	1
Socket	FCBGA1440	FCBGA1744
Power consumption (TDP)	45 Watt	15 Watt

Technologies and extensions

Technological solutions and additional instructions supported by Core i5-8400H and Core i7-1255U. You'll probably need this information if you require some particular technology.

Instruction set extensions	Intel® SSE4.1, Intel® SSE4.2, Intel® AVX2	Intel® SSE4.1, Intel® SSE4.2, Intel® AVX2
AES-NI	+	+
FMA	-	+
AVX	+	+
vPro	+	no data
Enhanced SpeedStep (EIST)	+	+
Speed Shift	+	+
My WiFi	+	no data
Turbo Boost Technology	2.0	no data
Hyper-Threading Technology	+	+
TSX	+	+
Idle States	+	no data
Thermal Monitoring	+	+
Flex Memory Access	+	+
SIPP	+	-
Deep Learning Boost	-	+

Security technologies

Core i5-8400H and Core i7-1255U technologies aimed at improving security, for example, by protecting against hacks.

TXT	+	+
EDB	+	+
Secure Key	+	+
MPX	+	-
Identity Protection	+	-
SGX	Yes with Intel® ME	no data
OS Guard	+	+

Virtualization technologies

Virtual machine speed-up technologies supported by Core i5-8400H and Core i7-1255U are enumerated here.

AMD-V	+	-
VT-d	+	+
VT-x	+	+
EPT	+	+

Memory specs

Types, maximum amount and channel quantity of RAM supported by Core i5-8400H and Core i7-1255U. Depending on the motherboard, higher memory frequencies may be supported.

Supported memory types	DDR4	DDR4, DDR5
Maximum memory size	64 GB	64 GB
Max memory channels	2	2
Maximum memory bandwidth	42.671 GB/s	no data

Graphics specifications

General parameters of integrated GPUs, if any.

Integrated graphics card	Intel UHD Graphics 630	Intel® Iris® Xe Graphics eligible
Max video memory	64 GB	no data
Quick Sync Video	+	+
Clear Video	+	no data
Clear Video HD	+	no data
Graphics max frequency	1.1 GHz	1.25 GHz
Execution Units	no data	96
InTru 3D	+	no data

Graphics interfaces

Available interfaces and connections of Core i5-8400H and Core i7-1255U integrated GPUs.

Number of displays supported	3	4
eDP	+	no data
DisplayPort	+	-
HDMI	+	-
DVI	+	no data

Graphics image quality

Maximum display resolutions supported by Core i5-8400H and Core i7-1255U integrated GPUs, including resolutions over different interfaces.

4K resolution support	+	no data
Max resolution over HDMI 1.4	4096x2304@30Hz	4096 x 2304 @ 60Hz
Max resolution over eDP	4096x2304@60Hz	4096 x 2304 @ 120Hz
Max resolution over DisplayPort	4096x2304@60Hz	7680 x 4320 @ 60Hz
Max resolution over VGA	N/A	no data

Graphics API support

APIs supported by Core i5-8400H and Core i7-1255U integrated GPUs, sometimes API versions are included.

DirectX	12	12.1
OpenGL	4.5	4.6

Peripherals

Specifications and connection of peripherals supported by Core i5-8400H and Core i7-1255U.

PCIe version	3.0	4.0
PCI Express lanes	16	20

Synthetic benchmark performance

Various benchmark results of the processors in comparison. Overall score is measured in points in 0-100 range, higher is better.

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Combined synthetic benchmark score

This is our combined benchmark performance rating. We are regularly improving our combining algorithms, but if you find some perceived inconsistencies, feel free to speak up in comments section, we usually fix problems quickly.

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Pros & cons summary

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Performance score	4.81	8.54
Recency	2 April 2018	23 February 2022
Physical cores	4	10
Threads	8	12
Power consumption (TDP)	45 Watt	15 Watt

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Should you still have questions on choice between Core i5-8400H and Core i7-1255U, ask them in Comments section, and we shall answer.

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