GhostRider hotfixes

- Added average hashrate display
- Fixed the number of threads shown at startup
- Fixed `--threads` or `-t` command line option (but `--cpu-max-threads-hint` is recommended to use)

src/crypto/ghostrider/README.md

@@ -18,11 +18,13 @@ xmrig -a gr -o us.flockpool.com:5555 --tls -u WALLET_ADDRESS
 
 You can use **rtm_ghostrider_example.cmd** as a template and put pool URL and your wallet address there. The general XMRig documentation is available [here](https://xmrig.com/docs/miner).
 
+**Using `--threads` or `-t` option is NOT recommended because it turns off advanced built-in config.** If you want to tweak the nubmer of threads used for GhostRider, it's recommended to start using config.json instead of command line. The best suitable command line option for this is `--cpu-max-threads-hint=N` where N can be between 0 and 100.
+
 ## Performance
 
 While individual algorithm implementations are a bit unoptimized, XMRig achieves higher hashrates by employing better auto-config and more fine-grained thread scheduling: it can calculate a single batch of hashes using 2 threads for parts that don't require much cache. For example, on a typical Intel CPU (2 MB cache per core) it will use 1 thread per core for cn/fast, and 2 threads per core for other Cryptonight variants while calculating the same batch of hashes, always achieving more than 50% CPU load.
 
-For the same reason, XMRig can sometimes use less than 100% CPU on Ryzen 3000/5000 CPUs if it finds that running 1 thread per core is faster for some Cryptonight variants on your system. Also, this is why it reports using only half the threads at startup - it's actually 2 threads per each reported thread.
+For the same reason, XMRig can sometimes use less than 100% CPU on Ryzen 3000/5000 CPUs if it finds that running 1 thread per core is faster for some Cryptonight variants on your system.
 
 **Windows** (detailed results [here](https://imgur.com/a/GCjEWpl))
 CPU|cpuminer-gr-avx2 (tuned), h/s|XMRig (MSVC build), h/s|Speedup