diff --git a/Machines/PCCompatible/PCCompatible.cpp b/Machines/PCCompatible/PCCompatible.cpp
index fb51daf42..ef0aa6a8c 100644
--- a/Machines/PCCompatible/PCCompatible.cpp
+++ b/Machines/PCCompatible/PCCompatible.cpp
@@ -49,15 +49,12 @@
 
 namespace PCCompatible {
 
-using VideoAdaptor = Analyser::Static::PCCompatible::Target::VideoAdaptor;
+using Target = Analyser::Static::PCCompatible::Target;
 
-template <VideoAdaptor adaptor> struct Adaptor;
-template <> struct Adaptor<VideoAdaptor::MDA> {
-	using type = MDA;
-};
-template <> struct Adaptor<VideoAdaptor::CGA> {
-	using type = CGA;
-};
+// Map from members of the VideoAdaptor enum to concrete class types.
+template <Target::VideoAdaptor adaptor> struct Adaptor;
+template <> struct Adaptor<Target::VideoAdaptor::MDA> {		using type = MDA;	};
+template <> struct Adaptor<Target::VideoAdaptor::CGA> {		using type = CGA;	};
 
 class FloppyController {
 	public:
@@ -500,7 +497,7 @@ using PIT = i8253<false, PITObserver>;
 
 class i8255PortHandler : public Intel::i8255::PortHandler {
 	public:
-		i8255PortHandler(PCSpeaker &speaker, KeyboardController &keyboard, VideoAdaptor adaptor, int drive_count) :
+		i8255PortHandler(PCSpeaker &speaker, KeyboardController &keyboard, Target::VideoAdaptor adaptor, int drive_count) :
 			speaker_(speaker), keyboard_(keyboard) {
 				// High switches:
 				//
@@ -508,8 +505,8 @@ class i8255PortHandler : public Intel::i8255::PortHandler {
 				// b1, b0: video mode (00 = ROM; 01 = CGA40; 10 = CGA80; 11 = MDA)
 				switch(adaptor) {
 					default: break;
-					case VideoAdaptor::MDA:	high_switches_ |= 0b11;	break;
-					case VideoAdaptor::CGA:	high_switches_ |= 0b10;	break;	// Assume 80 columns.
+					case Target::VideoAdaptor::MDA:	high_switches_ |= 0b11;	break;
+					case Target::VideoAdaptor::CGA:	high_switches_ |= 0b10;	break;	// Assume 80 columns.
 				}
 				high_switches_ |= uint8_t(drive_count << 2);
 
@@ -593,7 +590,7 @@ class i8255PortHandler : public Intel::i8255::PortHandler {
 };
 using PPI = Intel::i8255::i8255<i8255PortHandler>;
 
-template <VideoAdaptor video>
+template <Target::VideoAdaptor video>
 class IO {
 	public:
 		IO(PIT &pit, DMA &dma, PPI &ppi, PIC &pic, typename Adaptor<video>::type &card, FloppyController &fdc, RTC &rtc) :
@@ -601,7 +598,7 @@ class IO {
 
 		template <typename IntT> void out(uint16_t port, IntT value) {
 			static constexpr uint16_t crtc_base =
-				video == VideoAdaptor::MDA ? 0x03b0 : 0x03d0;
+				video == Target::VideoAdaptor::MDA ? 0x03b0 : 0x03d0;
 
 			switch(port) {
 				default:
@@ -772,13 +769,13 @@ class IO {
 				case 0x03f5:	return fdc_.read();
 
 				case 0x03b8:
-					if constexpr (video == VideoAdaptor::MDA) {
+					if constexpr (video == Target::VideoAdaptor::MDA) {
 						return video_.template read<0x8>();
 					}
 				break;
 
 				case 0x3da:
-					if constexpr (video == VideoAdaptor::CGA) {
+					if constexpr (video == Target::VideoAdaptor::CGA) {
 						return video_.template read<0xa>();
 					}
 				break;
@@ -860,7 +857,7 @@ class FlowController {
 		bool halted_ = false;
 };
 
-template <VideoAdaptor video, bool turbo>
+template <Target::VideoAdaptor video>
 class ConcreteMachine:
 	public Machine,
 	public MachineTypes::TimedMachine,
@@ -887,6 +884,9 @@ class ConcreteMachine:
 			ppi_(ppi_handler_),
 			context(pit_, dma_, ppi_, pic_, video_, fdc_, rtc_)
 		{
+			// Capture speed.
+			speed_ = target.speed;
+
 			// Set up DMA source/target.
 			dma_.set_memory(&context.memory);
 
@@ -900,17 +900,21 @@ class ConcreteMachine:
 			const auto tick = ROM::Name::PCCompatibleGLaTICK;
 			const auto font = Video::FontROM;
 
-			ROM::Request request = ROM::Request(bios) && ROM::Request(tick) && ROM::Request(font);
+			ROM::Request request = ROM::Request(bios) && ROM::Request(tick, true) && ROM::Request(font);
 			auto roms = rom_fetcher(request);
 			if(!request.validate(roms)) {
 				throw ROMMachine::Error::MissingROMs;
 			}
 
+			// A BIOS is mandatory.
 			const auto &bios_contents = roms.find(bios)->second;
 			context.memory.install(0x10'0000 - bios_contents.size(), bios_contents.data(), bios_contents.size());
 
-			const auto &tick_contents = roms.find(tick)->second;
-			context.memory.install(0xd'0000, tick_contents.data(), tick_contents.size());
+			// If found, install GlaTICK at 0xd'0000.
+			auto tick_contents = roms.find(tick);
+			if(tick_contents != roms.end()) {
+				context.memory.install(0xd'0000, tick_contents->second.data(), tick_contents->second.size());
+			}
 
 			// Give the video card something to read from.
 			const auto &font_contents = roms.find(font)->second;
@@ -926,15 +930,23 @@ class ConcreteMachine:
 
 		// MARK: - TimedMachine.
 		void run_for(const Cycles duration) override {
+			switch(speed_) {
+				case Target::Speed::ApproximatelyOriginal:	run_for<Target::Speed::ApproximatelyOriginal>(duration);	break;
+				case Target::Speed::Fast: 					run_for<Target::Speed::Fast>(duration);						break;
+			}
+		}
+
+		template <Target::Speed speed>
+		void run_for(const Cycles duration) {
 			const auto pit_ticks = duration.as<int>();
 
 			int ticks;
-			if constexpr (!turbo) {
+			if constexpr (speed == Target::Speed::Fast) {
+				ticks = pit_ticks;
+			} else {
 				cpu_divisor_ += pit_ticks;
 				ticks = cpu_divisor_ / 3;
 				cpu_divisor_ %= 3;
-			} else {
-				ticks = pit_ticks;
 			}
 
 			while(ticks--) {
@@ -948,7 +960,9 @@ class ConcreteMachine:
 				pit_.run_for(1);
 				++speaker_.cycles_since_update;
 
-				if constexpr (!turbo) {
+				// For original speed, the CPU performs instructions at a 1/3rd divider of the PIT clock,
+				// so run the PIT three times per 'tick'.
+				if constexpr (speed == Target::Speed::ApproximatelyOriginal) {
 					pit_.run_for(1);
 					++speaker_.cycles_since_update;
 					pit_.run_for(1);
@@ -958,7 +972,7 @@ class ConcreteMachine:
 				//
 				// Advance CRTC at a more approximate rate.
 				//
-				video_.run_for(turbo ? Cycles(1) : Cycles(3));
+				video_.run_for(speed == Target::Speed::Fast ? Cycles(1) : Cycles(3));
 
 				//
 				// Give the keyboard a notification of passing time; it's very approximately clocked,
@@ -992,8 +1006,8 @@ class ConcreteMachine:
 					continue;
 				}
 
-				if constexpr (turbo) {
-					// There's no divider applied, so this makes for 2*PI = around 2.4 MIPS.
+				if constexpr (speed == Target::Speed::Fast) {
+					// There's no divider applied, so this makes for 2*PIT = around 2.4 MIPS.
 					// That's broadly 80286 speed, if MIPS were a valid measure.
 					perform_instruction();
 					perform_instruction();
@@ -1176,6 +1190,7 @@ class ConcreteMachine:
 		std::pair<int, InstructionSet::x86::Instruction<false>> decoded;
 
 		int cpu_divisor_ = 0;
+		Target::Speed speed_{};
 };
 
 
@@ -1185,21 +1200,12 @@ using namespace PCCompatible;
 
 // See header; constructs and returns an instance of the Amstrad CPC.
 Machine *Machine::PCCompatible(const Analyser::Static::Target *target, const ROMMachine::ROMFetcher &rom_fetcher) {
-	using Target = Analyser::Static::PCCompatible::Target;
 	const Target *const pc_target = dynamic_cast<const Target *>(target);
 
-	if(pc_target->speed == Target::Speed::Fast) {
-		switch(pc_target->adaptor) {
-			case VideoAdaptor::MDA:	return new PCCompatible::ConcreteMachine<VideoAdaptor::MDA, true>(*pc_target, rom_fetcher);
-			case VideoAdaptor::CGA:	return new PCCompatible::ConcreteMachine<VideoAdaptor::CGA, true>(*pc_target, rom_fetcher);
-			default: return nullptr;
-		}
-	} else {
-		switch(pc_target->adaptor) {
-			case VideoAdaptor::MDA:	return new PCCompatible::ConcreteMachine<VideoAdaptor::MDA, false>(*pc_target, rom_fetcher);
-			case VideoAdaptor::CGA:	return new PCCompatible::ConcreteMachine<VideoAdaptor::CGA, false>(*pc_target, rom_fetcher);
-			default: return nullptr;
-		}
+	switch(pc_target->adaptor) {
+		case Target::VideoAdaptor::MDA:	return new PCCompatible::ConcreteMachine<Target::VideoAdaptor::MDA>(*pc_target, rom_fetcher);
+		case Target::VideoAdaptor::CGA:	return new PCCompatible::ConcreteMachine<Target::VideoAdaptor::CGA>(*pc_target, rom_fetcher);
+		default: return nullptr;
 	}
 }
 
diff --git a/Machines/Utility/ROMCatalogue.cpp b/Machines/Utility/ROMCatalogue.cpp
index 0332dab33..b217c000e 100644
--- a/Machines/Utility/ROMCatalogue.cpp
+++ b/Machines/Utility/ROMCatalogue.cpp
@@ -581,6 +581,13 @@ Description::Description(Name name) {
 		case Name::PCCompatibleMDAFont:
 			*this = Description(name, "PCCompatible", "IBM's MDA font", "EUMDA9.F14", 14 * 256, 0x7754882au);
 		break;
+		case Name::PCCompatibleEGABIOS:
+			*this = Description(name, "PCCompatible", "IBM's EGA BIOS", "ibm_6277356_ega_card_u44_27128.bin", 16 * 1024, 0x2f2fbc40u);
+		break;
+		case Name::PCCompatibleVGABIOS:
+			*this = Description(name, "PCCompatible", "IBM's VGA BIOS", "ibm_vga.bin", 32 * 1024, 0x03b3f90du);
+		break;
+
 
 		// TODO: CRCs below are incomplete, at best.
 		case Name::MSXGenericBIOS:	*this = Description(name, "MSX", "a generix MSX BIOS", "msx.rom", 32*1024, 0x94ee12f3u);			break;
diff --git a/Machines/Utility/ROMCatalogue.hpp b/Machines/Utility/ROMCatalogue.hpp
index 8d223cae4..f82cb959d 100644
--- a/Machines/Utility/ROMCatalogue.hpp
+++ b/Machines/Utility/ROMCatalogue.hpp
@@ -135,8 +135,11 @@ enum Name {
 	PCCompatibleGLaBIOS,
 	PCCompatibleGLaTICK,
 	PCCompatiblePhoenix80286BIOS,
+
 	PCCompatibleMDAFont,
 	PCCompatibleCGAFont,
+	PCCompatibleEGABIOS,
+	PCCompatibleVGABIOS,
 
 	// Sinclair QL.
 	SinclairQLJS,
diff --git a/ROMImages/PCCompatible/readme.txt b/ROMImages/PCCompatible/readme.txt
index d15254705..bcae61063 100644
--- a/ROMImages/PCCompatible/readme.txt
+++ b/ROMImages/PCCompatible/readme.txt
@@ -1,14 +1,24 @@
 Expected files:
 
-GLABIOS_0.2.5_8T.ROM — the 8088 GLaBIOS ROM.
-GLaTICK_0.8.5_AT.ROM — the GLaBIOS AT RTC option ROM.
-Phoenix 80286 ROM BIOS Version 3.05.bin — Phoenix's 80286 AT-clone BIOS.
-EUMDA9.F14 — a dump of the MDA font.
-CGA.F08 — a dump of the CGA font.
+For XT-class emulation:
+
+	GLABIOS_0.2.5_8T.ROM — the 8088 GLaBIOS ROM.
+	GLaTICK_0.8.5_AT.ROM (optionally) — the GLaBIOS AT RTC option ROM.
+
+For specific video cards:
+
+	EUMDA9.F14 — the MDA font.
+	CGA.F08 — the CGA font.
+
+In the future:
+
+	Phoenix 80286 ROM BIOS Version 3.05.bin — Phoenix's 80286 AT-clone BIOS.
+	ibm_vga.bin — the VGA BIOS.
+	ibm_6277356_ega_card_u44_27128.bin — the EGA BIOS.
 
 
 GLaBIOS is an open-source GPLv3 alternative BIOS for XT clones, available from https://glabios.org/
 
 GLaTICK is a real-time clock option ROM, also available from available from https://glabios.org/
 
-The MDA and CGA fonts are in the form offered at https://github.com/viler-int10h/vga-text-mode-fonts i.e. it's 256 lots of 14 bytes, the first 14 being the content of character 0, the next 14 being the content of character 1, etc.
\ No newline at end of file
+The MDA and CGA fonts are in the form offered at https://github.com/viler-int10h/vga-text-mode-fonts i.e. the MDA font is 256 lots of 14 bytes, the first 14 being the content of character 0, the next 14 being the content of character 1, etc; the CGA font is 256 lots of 8 bytes with a corresponding arrangement.
\ No newline at end of file
diff --git a/Storage/Disk/Encodings/MFM/Constants.hpp b/Storage/Disk/Encodings/MFM/Constants.hpp
index 838e7d34e..ec8cea788 100644
--- a/Storage/Disk/Encodings/MFM/Constants.hpp
+++ b/Storage/Disk/Encodings/MFM/Constants.hpp
@@ -44,6 +44,7 @@ const Time FMBitLength					= Time(1, 50000);
 
 constexpr Time bit_length(Density density) {
 	switch(density) {
+		default:
 		case Density::Single:	return FMBitLength;
 		case Density::Double:	return MFMBitLength;
 		case Density::High:		return HDMFMBitLength;
diff --git a/Storage/Disk/Encodings/MFM/Encoder.cpp b/Storage/Disk/Encodings/MFM/Encoder.cpp
index 0379fadab..aa05f47f9 100644
--- a/Storage/Disk/Encodings/MFM/Encoder.cpp
+++ b/Storage/Disk/Encodings/MFM/Encoder.cpp
@@ -382,6 +382,7 @@ std::shared_ptr<Storage::Disk::Track> Storage::Encodings::MFM::TrackWithSectors(
 	std::optional<uint8_t> sector_gap_filler_byte
 ) {
 	switch(density) {
+		default:
 		case Density::Single:	return TTrackWithSectors<Density::Single>(sectors, sector_gap_length, sector_gap_filler_byte);
 		case Density::Double:	return TTrackWithSectors<Density::Double>(sectors, sector_gap_length, sector_gap_filler_byte);
 		case Density::High:		return TTrackWithSectors<Density::High>(sectors, sector_gap_length, sector_gap_filler_byte);