diff --git a/src/block_cache.cpp b/src/block_cache.cpp
index 2aaa87d..2cac247 100644
--- a/src/block_cache.cpp
+++ b/src/block_cache.cpp
@@ -154,6 +154,7 @@ struct BlockCache::Impl : public nocopy_nomove
 BlockCache::BlockCache()
 	: m_impl(new Impl())
 	, m_flushRunning(0)
+	, m_storeIndex(0)
 {
 }
 
@@ -171,7 +172,7 @@ void BlockCache::store(const PoolBlock& block)
 		return;
 	}
 
-	uint8_t* data = m_impl->m_data + (static_cast<size_t>(block.m_sidechainHeight % NUM_BLOCKS) * BLOCK_SIZE);
+	uint8_t* data = m_impl->m_data + (static_cast<size_t>((m_storeIndex++) % NUM_BLOCKS) * BLOCK_SIZE);
 
 	*reinterpret_cast<uint32_t*>(data) = static_cast<uint32_t>(n1 + n2);
 	memcpy(data + sizeof(uint32_t), block.m_mainChainData.data(), n1);
diff --git a/src/block_cache.h b/src/block_cache.h
index d9fd27b..ab22b32 100644
--- a/src/block_cache.h
+++ b/src/block_cache.h
@@ -37,6 +37,7 @@ private:
 	struct Impl;
 	Impl* m_impl;
 	std::atomic<uint32_t> m_flushRunning;
+	std::atomic<uint32_t> m_storeIndex;
 };
 
 } // namespace p2pool
diff --git a/src/side_chain.cpp b/src/side_chain.cpp
index 199121f..286cb5e 100644
--- a/src/side_chain.cpp
+++ b/src/side_chain.cpp
@@ -514,11 +514,6 @@ void SideChain::add_block(const PoolBlock& block)
 		", verified = " << (block.m_verified ? 1 : 0)
 	);
 
-	// Save it for faster syncing on the next p2pool start
-	if (p2pServer()) {
-		p2pServer()->store_in_cache(block);
-	}
-
 	PoolBlock* new_block = new PoolBlock(block);
 
 	MutexLock lock(m_sidechainLock);
@@ -541,6 +536,11 @@ void SideChain::add_block(const PoolBlock& block)
 	if (new_block->m_verified) {
 		if (!new_block->m_invalid) {
 			update_chain_tip(new_block);
+
+			// Save it for faster syncing on the next p2pool start
+			if (P2PServer* server = p2pServer()) {
+				server->store_in_cache(*new_block);
+			}
 		}
 	}
 	else {
@@ -1013,17 +1013,19 @@ void SideChain::verify_loop(PoolBlock* block)
 					", height " << block->m_sidechainHeight);
 			}
 
+			P2PServer* server = p2pServer();
+
 			// If it came through a broadcast, send it to our peers
 			if (block->m_wantBroadcast && !block->m_broadcasted) {
 				block->m_broadcasted = true;
-				if (p2pServer() && (block->m_depth < UNCLE_BLOCK_DEPTH)) {
-					p2pServer()->broadcast(*block);
+				if (server && (block->m_depth < UNCLE_BLOCK_DEPTH)) {
+					server->broadcast(*block);
 				}
 			}
 
 			// Save it for faster syncing on the next p2pool start
-			if (p2pServer()) {
-				p2pServer()->store_in_cache(*block);
+			if (server) {
+				server->store_in_cache(*block);
 			}
 
 			// Try to verify blocks on top of this one