Intel is continuing to measure and evaluate the performance impact of their own firmware changes to address the SPECTRE and MELTDOWN exploits. Click on the chart to view the results in full size.
The chart shows Intel’s measurements for certain 6th, 7th and 8th generation Intel processors. The measurements are made using standard “benchmarket” tests that simulate specific usage scenarios. Consequently, these are measurements of performance impacts to these benchmark tests, which may not represent how we use our own computers.
Source: Intel Security Issue Update: Initial Performance Data Results for Client Systems
Separately, Google says they managed to upgrade their cloud servers with their own fixes that had negligible impacts.
While AMD processors appear to not be impacted by the MELTDOWN exploit, AMD did announce that one of the variants of SPECTRE does impact the AMD processors.
This suggests that over the weeks and months to come, future updates may appear that fix new variations of the exploits but also improve performance as better solutions are identified.