Why is mining hashrate by monero-gui-v0.17.3.1 significantly slower than xmrig-6.16.2-focal-x64?

Question

I have been experimenting with solo mining Monero using two approaches on the same machine: monero-gui-v0.17.3.1 and xmrig-6.16.2-focal-x64. The monero-gui reported a hash rate of ~6KH/s while xmrig reported ~10KH/s.

monero-gui:

xmrig:

Questions:

1. Why is the hash rate of these two approaches different?
2. Is there any way to improve the hash rate of monero-gui or monero-x86_64-linux-gnu-v0.17.3.0? Is there some options that I can apply to the monerod?
3. Where can I find the documentation of the mining algorithm used by monero-gui or monero-x86_64-linux-gnu-v0.17.3.0?

To check the xmrig reported hashrate, I also experimented mining Monero in a pool for an hour. It fluctuated between 4KH/s to 17KH/s and achieved an hourly hashrate of 10.42KH/s (see below). Although I did not see such large fluctuations in hashrate on my local terminal as it always maintained around ~10KH/s, this result shows the hashrate reported by xmrig is reliable/consistent. When solo mining with monero-gui, I have never seen the hashrate reach 7KH/s on this same system, meaning the computation algorithm appears to be substantially slower than xmrig. Given that the official Monero wallet is encouraged to be used and encourages solo mining to improve the decentralization of Moenro, a reasonable expectation is the monero-gui-wallet should provide a fast mining algorithm.

Answer 1

1. The Monero wallet is a wallet that happens to also ask the Monero daemon to mine. XMRig is a dedicated miner – it is built to do one thing and do that one thing as best as it can.
2. No, not really.
3. https://github.com/tevador/RandomX/tree/master/doc