The Intel X299 motherboards have been rushed and it seems that the design quality is not as great as what we are used to. With that said, motherboard partners are not the ones to blame here. Intel is the culprit, as the company pushed the X299 platform from August to June which left motherboard manufacturers little time for anything to do.
Overclocker Der8auer voiced his concern regarding Intel X299 motherboards and he noted that there is a VRM cooling issue that causes the CPU to throttle and hence clock down. This also means that the CPU does not overclock all that well. VRM heatsinks featured on the Intel X299 motherboards do not do justice to the price.
If you are paying $300 or more for a motherboard then you expect to have proper VRM heatsinks and thermal pads in order to provide proper heat dissipation. Other than that Der8auer also talked about 8-pin connectors for the CPUs and that a single 8-pin connector is not enough for overclocking. He noted that the temperature of the power cable went up extremely high.
This can be a fire hazard and he has made it clear that you should stay away from Intel X299 motherboards that feature a single 8-pin power connector for the CPU. In some cases, the VRM temperatures went up to 100C. This is something that you do not want. You can check out the complete video below.
It has been noted that if you remove the VRM heatsinks and place a small fan on top then this reduces the temperature by about 40C. This clearly means that the thermal pads and the heatsinks that are being used are not at all good.
If you are in the market for an Intel X299 motherboard then it would be best that you hold on for a month or two and let motherboard partners bring something better to the table. If you have not bought an X series CPU yet then you might want to wait a little longer.