Select any two CPUs for comparison
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Gaming Performance Comparison

Recommended System Requirements
Game Celeron M ULV 423 1.06GHz Celeron Mobile 266MHz
Cyberpunk 2077 3731% 142757%
Minecraft: Dungeons 3731% 142757%
Call of Duty Warzone 3243% 124557%
Grand Theft Auto VI 6448% 244043%
Assassins Creed: Valhalla 4728% 179900%
Valorant 2209% 85986%
Maneater 3731% 142757%
Phantasy Star Online 2 712% 30171%
Doom Eternal 5264% 199900%
Mount and Blade 2: Bannerlord 5973% 226329%

In terms of overall gaming performance, the Intel Celeron M ULV 423 1.06GHz is very slightly better than the Intel Celeron Mobile 266MHz when it comes to running the latest games. This also means it will be less likely to bottleneck more powerful GPUs, allowing them to achieve more of their gaming performance potential.

The Celeron M ULV was released over three years more recently than the Celeron Mobile 266MHz, and so the Celeron M ULV is likely to have far better levels of support, and will be much more optimized and ultimately superior to the Celeron Mobile 266MHz when running the latest games.

Both CPUs exhibit very poor performance, so rather than upgrading from one to the other you should consider looking at more powerful CPUs. Neither of these will be able to run the latest games in any playable way.

The Celeron M ULV and the Celeron Mobile 266MHz both have 1 cores, and so are quite likely to struggle with the latest games, or at least bottleneck high-end graphics cards when running them. With a decent accompanying GPU, the Celeron M ULV and the Celeron Mobile 266MHz may still be able to run slightly older games fairly effectively.

More important for gaming than the number of cores and threads is the clock rate. Problematically, unless the two CPUs are from the same family, this can only serve as a general guide and nothing like an exact comparison, because the clock cycles per instruction (CPI) will vary so much.

The Celeron M ULV and Celeron Mobile 266MHz are not from the same family of CPUs, so their clock speeds are by no means directly comparable. Bear in mind, then, that while the Celeron M ULV has a 0.794 GHz faster frequency, this is not always an indicator that it will be superior in performance, despite frequency being crucial when trying to avoid GPU bottlenecking. In this case, however, the difference is probably a good indicator that the is superior.

Aside from the clock rate, the next-most important CPU features for PC game performance are L2 and L3 cache size. Faster than RAM, the more cache available, the more data that can be stored for lightning-fast retrieval. L1 Cache is not usually an issue anymore for gaming, with most high-end CPUs eking out about the same L1 performance, and L2 is more important than L3 - but L3 is still important if you want to reach the highest levels of performance. Bear in mind that although it is better to have a larger cache, the larger it is, the higher the latency, so a balance has to be struck.

The Celeron Mobile 266MHz has a 127 KB bigger L2 cache than the Celeron M ULV, but neither of the CPUs have L3 caches, so the Celeron Mobile 266MHz wins out in this area with its larger L2 cache.

The System Bus Speed is important for providing higher bandwidth, and with higher bandwidth the system has the capacity to move more data over a certain time period than it would with lower bandwidth.

The Celeron M ULV has a 467 MHz faster System Bus Speed than the Celeron Mobile 266MHz, and as such, has a significantly higher limit when it comes to the size of the data being processed at once.

The maximum Thermal Design Power is the power in Watts that the CPU will consume in the worst case scenario. The lithography is the semiconductor manufacturing technology being used to create the CPU - the smaller this is, the more transistors that can be fit into the CPU, and the closer the connections. For both the lithography and the TDP, it is the lower the better, because a lower number means a lower amount of power is necessary to run the CPU, and consequently a lower amount of heat is produced.

The Celeron Mobile 266MHz has a 45 Watt lower Maximum TDP than the Celeron M ULV. However, the Celeron M ULV was created with a 185 nm smaller manufacturing technology. Overall, by taking both into account, the Celeron M ULV is likely the CPU with the lower heat production and power requirements, by quite a wide margin.

CPU Core Details

CPU Codename-Mendocino
MoBo SocketSocket 479Socket 370
Notebook CPUyesyes
Release Date01 Jul 200625 Jan 1999
CPU LinkGD LinkGD Link
Approved

CPU Technical Specifications

CPU Cores1vs1
Clock Speed1.06 GHzvs0.266 GHz
Turbo Frequency-vs-
System Bus 533 MHzvs66 MHz
Max TDP55 Wvs10 W
Lithography65 nmvs250 nm
Bit Width32 Bitvs-
Voltage Range0.85V-1.10V KBvs1.6V KB
Max Temperature-vs100°C
Virtualization Technologynovsno
Comparison

CPU Cache and Memory

L1 Cache Size-vs32 KB
L2 Cache Size1 KBvs128 KB
L2 Cache Speed-vs-
L3 Cache Size-vs-
ECC Memory Supportnovsno
Comparison

CPU Graphics

Graphics
Base GPU Frequency-vs-
Max GPU Frequency-vs-
DirectX-vs-
Displays Supported-vs-
Comparison

CPU Package and Version Specifications

Package Size35mm x 35mmvs-
Revision-vs-
PCIe Revision-vs-
PCIe Configurations-vs-

Gaming Performance Value

Performance Value

CPU Mini Review

Mini ReviewMerom is the code name for various Intel processors that are sold as Core 2 Duo, Core 2 Solo, Pentium Dual-Core and Celeron. It was the first mobile processor to be based on the Core microarchitecture, replacing the Enhanced Pentium M based Yonah processor. Merom has product code 80537, which is shared with Merom-2M and Merom-L that are very similar but have a smaller L2 cache. Merom-L has only one processor core and a different CPUID model. The desktop version of Merom is Conroe and the dual-socket server version is Woodcrest. Merom has subsequently been replaced by Penryn.The Mendocino Celeron, launched 24 August 1998, was the first retail CPU to use on-die L2 cache. Whereas Covington had no secondary cache at all, Mendocino included 128 KB of L2 cache running at full clock rate. The first Mendocino-core Celeron was clocked at a then-modest 300 MHz but offered almost twice the performance of the old cacheless Covington Celeron at the same clock rate. To distinguish it from the older Covington 300 MHz, Intel called the Mendocino core Celeron 300A. Although the other Mendocino Celerons (the 333 MHz part, for example) did not have an A appended, some people call all Mendocino processors Celeron-A regardless of clock rate.