No one can tell you what will be the max overclock for that CPU. Each CPU will be different, even if it is the same model, because of differences in the quality of the silicone batch it as made from, maufacturing variances, motherboard, cooling, etc. Overclocking is entirely experimental. The best you can do is research what others have done with that same CPU to get a rough idea of what it's capability is.
Have you stress tested the overclock to make sure it is stable? You need to put it under heavy load for a significant period of time to see if it holds up.
Download and install Prime95 and HWMonitor. Open HWMonior on the desktop where you can see the core temp section. Run Prime95 in "just stress testing" mode. Watch core temps. You want to keep them below 55c or so. Instability sets in much beyond that. If the computer doesn't lock up, restart or blue screen for two hours you pass the test.
What are you using for a CPU cooler?'
1.775 volts seems awfully high but it's been so long since I fooled with that generation of AMD CPUs I can't remember what is appropriate for voltages. What is the stock voltage?
You may need to increase RAM voltage or lower the starting RAM frequency in order to keep the RAM from causing instability. As the CPU frequency increases so will the RAM frequency. That's the reason.