15 W Core i5-1235U vs. 28 W Core i5-1135G7: Newer isn't always better

With Intel 12th gen laptops widely available, we now have a a handful of Alder Lake models in our database sporting everything from the Core i7-1255U to the Core i7-1260P to the Core i9-12900HX. The mobile 12th gen family thus far has been pretty good for the most part when it comes to performance even if performance-per-watt isn't always the best. Nonetheless, there is at least one particular SKU that we recommend users to think twice about.

After reviewing two separate models with the same Core i5-1235U option, we can comfortably say that this 12th gen CPU offers very little over the average i5-1135G7 in terms of overall performance. Single-thread performance may be a bit higher, but it's nothing to write home about. Laptops sporting the 11th gen Core i5-1135U are often less expensive as well which makes the Core i5-1235U that much less lucrative for buyers.

Moving one step up from the Core i5-1235U to the Core i7-1255U is actually quite significant as the latter can provide up to 60 percent faster multi-thread performance. The i5-1235U is a performance outlier in this regard and it can sometimes feel like a rebranded Core i5-1135G7 as a result.

Graphics performance from the integrated Iris Xe 80 EUs is actually weaker on the Core i5-1235U as well at roughly 10 to 15 percent slower than the average laptop in our database equipped with the same integrated GPU.

However, one aspect that the Core i5-1235U seems to have the upper hand on is power consumption. Our graph below compares the Core i5-1235U Vaio FE14 to the Core i5-1135G7 LG Gram 14 when running Prime95 on an external monitor. The LG system would consume about 39 percent more power despite both models showing roughly equal multi-thread performance. This aligns with the fact that the i5-1235U was designed under a 15 W TDP envelope compared to the 28 W i5-1135G7.

If you can't decide between a Core i5-1235U or Core i5-1135G7 laptop, then just keep in mind that the newer option offers roughly the same CPU performance and is more power efficient but at the cost of slower graphics performance. Upgrading to the Core i7-1255U instead can be a decent option if you want to stick to the 12th gen Core U-series.