I would concur with Byrd in more RAM and an accelerator. But 16Mg SIMMs is pretty cheap, you should be able to get it to 128MB with little problem. In fact, you should be able to do this for all your SE/30 as well. I do not know about the PB150, however, I think there is a limit as to how far it can go but if you can max it out it would be beneficial for it.
With the accelerator however, I have to caution you. Many people out there will sell you can accelerator pretty cheap (relatively speaking), but it has no software for it and each accelerator seem to have their own software for it, forcing you to hunt it down on the net. Some maybe easier to find than others. I'll make the hunt easier with this link, it has MOST (not all) of the known accelerators made for Mac: http://www.vintageapple.org/macdrivers/accel.shtml
You have a choice with accelerators - either a fast '030 or a '040 for the IIci. Since I have the DayStar '040 in my IIci, I'm partial to it. It fits into the Cache Card Slot nicely. It can be used with other Macs with an adapter. For the SE/30, I recommend the Diimo '030/50. It's small and fits inside the SE case. It also works on other Macs with an adapter. It will make the SE/30 a screaming wickedly fast Mac! But a '040 Accelerator will also need the '040 Cache Extension/Control Panel from Apple or the Accelerator maker. It turns on/off the two large caches inside the '040 as needed because many older programs crash under the '040 Cache and needs it off.
With the accelerator however, I have to caution you. Many people out there will sell you can accelerator pretty cheap (relatively speaking), but it has no software for it and each accelerator seem to have their own software for it, forcing you to hunt it down on the net. Some maybe easier to find than others. I'll make the hunt easier with this link, it has MOST (not all) of the known accelerators made for Mac: http://www.vintageapple.org/macdrivers/accel.shtml
You have a choice with accelerators - either a fast '030 or a '040 for the IIci. Since I have the DayStar '040 in my IIci, I'm partial to it. It fits into the Cache Card Slot nicely. It can be used with other Macs with an adapter. For the SE/30, I recommend the Diimo '030/50. It's small and fits inside the SE case. It also works on other Macs with an adapter. It will make the SE/30 a screaming wickedly fast Mac! But a '040 Accelerator will also need the '040 Cache Extension/Control Panel from Apple or the Accelerator maker. It turns on/off the two large caches inside the '040 as needed because many older programs crash under the '040 Cache and needs it off.