Filling all four slots with 8 GB DDR3-1600MHz DIMMs is the best way to reach the maximum 32 GB.
Limited overclocking capabilities. While the Z75 chipset supports it, the HP BIOS implementation is usually locked to stock speeds, although some memory profiles may be adjusted. pegatron 2ad5 manual
The Ultimate Pegatron 2AD5 Motherboard Manual & Upgrade Guide Filling all four slots with 8 GB DDR3-1600MHz
If you are trying to upgrade or repair one, here are the essential specs you would normally find in a manual: LGA 1155 (Supports Intel 2nd and 3rd Gen Core i3/i5/i7). Intel Z75. 4 DDR3 DIMM slots, supporting up to Expansion: pegatron 2ad5 manual
: Two USB 2.0 headers supporting up to 4 additional front-panel USB ports.